Neurodevelopmental disorders are a group of mental conditions negatively affecting the development of the

nervous system In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...

, which includes the

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

and

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

. According to the

American Psychiatric Association The American Psychiatric Association (APA) is the main professional organization of psychiatrists and trainee psychiatrists in the United States, and the largest psychiatric organization in the world. It has more than 39,200 members who are in ...

Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, (

DSM-5 The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the '' Diagnostic and Statistical Manual of Mental Disorders'', the taxonomic and diagnostic tool published by the American Psychiat ...

) published in 2013, these conditions generally appear in ''early'' childhood, usually before children start school, and can persist into adulthood. The key characteristic of all these disorders is that they negatively impact a person's functioning in one or more domains of life (personal, social, academic, occupational) depending on the disorder and deficits it has caused. All of these disorders and their levels of impairment exist on a spectrum, and affected individuals can experience varying degrees of symptoms and deficits, despite having the same diagnosis. The DSM-5 classifies neurodevelopmental disorders into six overarching groups:

intellectual An intellectual is a person who engages in critical thinking, research, and Human self-reflection, reflection about the nature of reality, especially the nature of society and proposed solutions for its normative problems. Coming from the wor ...

communication Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether Intention, unintentional or failed transmissions are included and whether communication not onl ...

autism Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...

, attention deficit hyperactivity,

motor An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gene ...

, and specific learning disorders. Often one disorder is accompanied by another.

Classification

Intellectual disability

Intellectual disability Intellectual disability (ID), also known as general learning disability (in the United Kingdom), and formerly mental retardation (in the United States), Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010).Archive is a generalized neurodevelopmental ...

, also known as ''general learning disability'' is a disorder that affects the ability to learn, retain, or process information; to think critically or abstractly, and to solve problems. Adaptive behaviour is limited, affecting daily living activities.

Global developmental delay Global developmental delay is an umbrella term used when children are significantly delayed in two or more areas of development. It can be diagnosed when a child is delayed in one or more milestones, categorised into motor skills, speech delay, spe ...

is categorized under intellectual disability and is diagnosed when several areas of intellectual functioning are affected.

Communication disorders

communication disorder A communication disorder is any disorder that affects an individual's ability to Speech perception, comprehend, detect, or apply language and speech to engage in dialogue effectively with others. This also encompasses deficiencies in verbal and N ...

is any disorder that affects an individual's ability to comprehend, detect, or apply

language Language is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and signed language, signed forms, and may also be conveyed through writing syste ...

and

speech Speech is the use of the human voice as a medium for language. Spoken language combines vowel and consonant sounds to form units of meaning like words, which belong to a language's lexicon. There are many different intentional speech acts, suc ...

to engage in dialogue effectively with others. This also encompasses deficiencies in verbal and

nonverbal communication Nonverbal communication is the transmission of messages or signals through a nonverbal platform such as eye contact (oculesics), body language (kinesics), social distance (proxemics), touch (Haptic communication, haptics), voice (prosody (lingui ...

styles. Examples include

stuttering Stuttering, also known as stammering, is a speech disorder characterized externally by involuntary repetitions and prolongations of sounds, syllables, words, or phrases as well as involuntary silent pauses called blocks in which the person who ...

, sound substitution, inability to understand or use one's native language.

Autism spectrum disorder

Autism Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...

, also called ''autism spectrum disorder'' (ASD) or ''autism spectrum condition'' (ASC), is a neurodevelopmental disorder characterized by symptoms of deficient reciprocal social communication and the presence of restricted, repetitive, and inflexible patterns of behavior. While its severity and specific manifestations vary widely across the spectrum, autism generally affects a person's ability to understand and connect with others and adapt to everyday situations. Like most developmental disorders, autism exists along a continuum of symptom severity, subjective distress, and functional impairment. A consequence of this dimensionality is substantial variability across autistic persons with respect to both the nature and the extent of required supports. A formal diagnosis of ASD requires not merely the presence of ASD symptoms, but symptoms that cause significant impairment in multiple domains of functioning, in addition to being excessive or atypical enough to be developmentally and

sociocultural {{Short pages monitor ADHD symptoms arise from executive dysfunction, and emotional dysregulation is often considered a core symptom. Difficulties in self-regulation such as time management, inhibition and sustained attention may cause poor professional performance, relationship difficulties and numerous health risks, collectively predisposing to a diminished quality of life and a direct average reduction in life expectancy of 13 years. ADHD is associated with other neurodevelopmental and

mental disorder A mental disorder, also referred to as a mental illness, a mental health condition, or a psychiatric disability, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. A mental disorder is ...

s as well as non-psychiatric disorders, which can cause additional impairment.

Motor disorders

Motor disorder Motor disorders are disorders of the nervous system that cause abnormal and involuntary movements. They can result from damage to the motor system. Motor disorders are defined in the fifth edition of the ''Diagnostic and Statistical Manual of Men ...

s including

developmental coordination disorder Developmental coordination disorder (DCD), also known as developmental motor coordination disorder, developmental dyspraxia, or simply dyspraxia (from Ancient Greek ''praxis'' 'activity'), is a neurodevelopmental disorder characterized by impai ...

stereotypic movement disorder Stereotypic movement disorder (SMD) is a motor disorder with onset in childhood involving restrictive and/or repetitive, nonfunctional motor behavior (e.g., hand waving or head banging), that markedly interferes with normal activities or results ...

, and

tic disorder Tic disorders are defined in the ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM) based on type (motor or phonic) and duration of tics (sudden, rapid, nonrhythmic movements). Tic disorders are defined similarly by the World Health ...

s (such as

Tourette's syndrome Tourette syndrome (TS), or simply Tourette's, is a common neurodevelopmental disorder that begins in childhood or adolescence. It is characterized by multiple movement (motor) tics and at least one vocal (phonic) tic. Common tics are blinki ...

), and

apraxia of speech Apraxia of speech (AOS), also called verbal apraxia, is a speech sound disorder affecting an individual's ability to translate conscious speech plans into motor plans, which results in limited and difficult speech ability. By the definition of a ...

Specific learning disorders

Deficits in any area of information processing can manifest in a variety of specific learning disabilities (SLD). It is possible for an individual to have more than one of these difficulties. This is referred to as comorbidity or co-occurrence of learning disabilities.

Currently being researched

There are

neurodevelopmental The development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The field ...

research projects examining potential new classifications of disorders including: #

Nonverbal learning disorder Nonverbal learning disorder (NVLD or NLD) is a proposed neurodevelopmental disorder characterized by core deficits in nonverbal skills, especially visual-spatial processing. People with this condition have normal or advanced verbal intelligence ...

(NLD or NVLD), a neurodevelopmental disorder thought to be linked to white matter in the right hemisphere of the brain and generally considered to include (a) low visuospatial intelligence; (b) discrepancy between verbal and visuospatial intelligence; (c) visuoconstructive and fine-motor coordination skills; (d) visuospatial memory tasks; (e) reading better than mathematical achievement; and (f) socioemotional skills. While Nonverbal learning disorder is not categorized in the ICD or DSM as a discrete classification, "the majority of researchers and clinicians agree that the profile of NLD clearly exists (but see Spreen, 2011, for an exception), but they disagree on the need for a specific clinical category and on the criteria for its identification."

Presentation

Consequences

The multitude of neurodevelopmental disorders spans a wide range of associated symptoms and severity, resulting in different degrees of mental, emotional, physical, and economic consequences for individuals, and in turn families, social groups, and society.

Causes

The

development of the nervous system The development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The field ...

is tightly regulated and timed; it is influenced by both genetic programs and the prenatal environment. Any significant deviation from the normal developmental trajectory early in life can result in missing or abnormal neuronal architecture or connectivity. Because of the temporal and spatial complexity of the developmental trajectory, there are many potential causes of neurodevelopmental disorders that may affect different areas of the nervous system at different times and ages. These range from social deprivation, genetic and

metabolic disease A metabolic disorder is a disorder that negatively alters the body's processing and distribution of macronutrients, such as proteins, fats, and carbohydrates. Metabolic disorders can happen when abnormal chemical reactions in the body alter the ...

immune disorder An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways: * By the component(s) of the immune system affected * By whether the immune system is overactive or underactive * By whether ...

infectious disease An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

nutrition Nutrition is the biochemistry, biochemical and physiology, physiological process by which an organism uses food and water to support its life. The intake of these substances provides organisms with nutrients (divided into Macronutrient, macro- ...

al factors,

physical trauma Injury is physiology, physiological damage to the living tissue of any organism, whether Injury in humans, in humans, Injury in animals, in other animals, or Injury in plants, in plants. Injuries can be caused in many ways, including mechanic ...

, and toxic and prenatal environmental factors. Some neurodevelopmental disorders, such as

and other

pervasive developmental disorder The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), was a group of disorders characterized by delays in the development of multiple basic functions including socialization and ...

s, are considered multifactorial

syndrome A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek language, Greek σύνδρομον, meaning "concurrence". When a sy ...

s which have many causes that converge to a more specific neurodevelopmental manifestation. Some deficits may be predicted from observed deviations in the maturation patterns of the infant gut

microbiome A microbiome () is the community of microorganisms that can usually be found living together in any given habitat. It was defined more precisely in 1988 by Whipps ''et al.'' as "a characteristic microbial community occupying a reasonably wel ...

Social deprivation

Deprivation from social and emotional care causes severe delays in brain and cognitive development. Studies with children growing up in Romanian orphanages during

Nicolae Ceauşescu Nicolae may refer to: * Nicolae (name), an Aromanian and Romanian name * ''Nicolae'' (novel), a 1997 novel See also *Nicolai (disambiguation) *Nicolao Nicolao is an Italian given name and a surname. It may refer to the following: Given name *Ni ...

's regime reveal profound effects of social deprivation and language deprivation on the developing brain. These effects are time-dependent. The longer children stayed in negligent institutional care, the greater the consequences. By contrast, adoption at an early age mitigated some of the effects of earlier

institutionalization In sociology, institutionalisation (or institutionalization) is the process of embedding some conception (for example a belief, norm, social role, particular value or mode of behavior) within an organization, social system, or society as a w ...

Genetic disorders

A prominent example of a genetically determined neurodevelopmental disorder is

trisomy A trisomy is a type of polysomy in which there are three instances of a particular chromosome, instead of the normal two. A trisomy is a type of aneuploidy (an abnormal number of chromosomes). Description and causes Most organisms that reprod ...

21, also known as Down syndrome. This disorder usually results from an extra

chromosome 21 Chromosome 21 is one of the 23 pairs of chromosomes in humans. Chromosome 21 is both the smallest human autosome and chromosome, with 46.7 million base pairs (the building material of DNA) representing about 1.5 percent of the total DNA in cell ...

, although in uncommon instances it is related to other chromosomal abnormalities such as translocation of the genetic material. It is characterized by short stature, epicanthal (

eyelid An eyelid ( ) is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. "Palpebral ...

) folds, abnormal

fingerprint A fingerprint is an impression left by the friction ridges of a human finger. The recovery of partial fingerprints from a crime scene is an important method of forensic science. Moisture and grease on a finger result in fingerprints on surfa ...

s, and palm prints, heart defects, poor

muscle tone In physiology, medicine, and anatomy, muscle tone (residual muscle tension or tonus) is the continuous and passive partial contraction of the muscles, or the muscle's resistance to passive stretch during resting state.O’Sullivan, S. B. (2007) ...

(delay of neurological development), and

intellectual disabilities Intellectual disability (ID), also known as general learning disability (in the United Kingdom), and formerly mental retardation (in the United States), Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010).Archive is a generalized neurodevelopmental ...

(delay of intellectual development). Less commonly known genetically determined neurodevelopmental disorders include

Fragile X syndrome Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder. The average IQ in males with FXS is under 55, while affected females tend to be in the borderline to normal range, typically around 70–85. Physical features may include a lo ...

. Fragile X syndrome was first described in 1943 by Martin and Bell, studying persons with family history of

sex-linked Sex linkage describes the sex-specific patterns of inheritance and expression when a gene is present on a sex chromosome (allosome) rather than a non-sex chromosome (autosome). Genes situated on the X-chromosome are thus termed X-linked, and a ...

"mental defects".

Rett syndrome Rett syndrome (RTT) is a genetic disorder that typically becomes apparent after 6–18 months of age and almost exclusively in girls. Symptoms include impairments in language and coordination, and repetitive movements. Those affected often h ...

, another X-linked disorder, produces severe functional limitations.

Williams syndrome Williams syndrome (WS), also Williams–Beuren syndrome (WBS), is a genetic disorder that affects many parts of the body. Facial features frequently include a broad forehead, underdeveloped chin, short nose, and full cheeks. Mild to moderate int ...

is caused by small deletions of genetic material from

chromosome 7 Chromosome 7 is one of the 23 pairs of chromosomes in humans, who normally have two copies of this chromosome. Chromosome 7 spans about 160 million base pairs (the building material of DNA) and represents between 5 and 5.5 percent of the total DN ...

. The most common recurrent

copy number variation Copy number variation (CNV) is a phenomenon in which sections of the genome are repeated and the number of repeats in the genome varies between individuals. Copy number variation is a type of structural variation: specifically, it is a type of ...

disorder is

DiGeorge syndrome DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a syndrome caused by a microdeletion on the long arm of chromosome 22. While the symptoms can vary, they often include congenital heart problems, specific facial features, frequent ...

(22q11.2 deletion syndrome), followed by Prader-Willi syndrome and

Angelman syndrome Angelman syndrome (AS) is a genetic disorder that affects approximately 1 in 15,000 individuals. AS impairs the function of the nervous system, producing symptoms, such as severe intellectual disability, developmental disability, limited to no ...

Immune dysfunction

Immune reactions during

pregnancy Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs ...

, both maternal and of the developing child, may produce neurodevelopmental disorders. One typical immune reaction in infants and children is

PANDAS Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) is a controversial hypothetical diagnosis for a subset of children with rapid onset of obsessive-compulsive disorder (OCD) or tic disorders. Sy ...

, or ''Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infection''. Another disorder is

Sydenham's chorea Sydenham's chorea, also known as rheumatic chorea, is a disorder characterized by Chorea, rapid, uncoordinated jerking movements primarily affecting the face, hands and feet. Sydenham's chorea is an autoimmune disease that results from childhood ...

, which results in more abnormal movements of the body and fewer psychological sequellae. Both are immune reactions against brain tissue that follow infection by ''

Streptococcus ''Streptococcus'' is a genus of gram-positive spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs along a sing ...

'' bacteria. Susceptibility to these immune diseases may be genetically determined, so sometimes several family members may have one or both of them following an

epidemic An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infection ...

of Strep infection.

Infectious diseases

Systemic infections can result in neurodevelopmental consequences, when they occur in infancy and childhood of humans, but would not be called a primary neurodevelopmental disorder. For example

HIV The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the im ...

Infections of the head and brain, like

brain abscess The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special sense ...

es,

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasion ...

encephalitis Encephalitis is inflammation of the Human brain, brain. The severity can be variable with symptoms including reduction or alteration in consciousness, aphasia, headache, fever, confusion, a stiff neck, and vomiting. Complications may include se ...

have a high risk of causing neurodevelopmental problems and eventually a disorder. For example,

measles Measles (probably from Middle Dutch or Middle High German ''masel(e)'', meaning "blemish, blood blister") is a highly contagious, Vaccine-preventable diseases, vaccine-preventable infectious disease caused by Measles morbillivirus, measles v ...

can progress to

subacute sclerosing panencephalitis Subacute sclerosing panencephalitis (SSPE), also known as Dawson disease, is a rare form of progressive brain inflammation caused by a persistent infection with the measles virus. The condition primarily affects children, teens, and young adults ...

. A number of

infectious diseases infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

can be transmitted congenitally (either before or at birth), and can cause serious neurodevelopmental problems, as for example the viruses HSV, CMV, rubella (

congenital rubella syndrome Congenital rubella syndrome (CRS) occurs when a human fetus is infected with the rubella virus (German measles) via maternal-fetal transmission and develops birth defects. The most common congenital defects affect the ophthalmologic, cardiac, a ...

Zika virus Zika virus (ZIKV; pronounced or ) is a member of the virus family ''Flaviviridae''. It is spread by daytime-active ''Aedes'' mosquitoes, such as '' A. aegypti'' and '' A. albopictus''. Its name comes from the Ziika Forest of Uganda, where ...

, or bacteria like ''Treponema pallidum'' in

congenital syphilis Congenital syphilis is syphilis that occurs when a mother with untreated syphilis passes the infection to her baby during pregnancy or at childbirth, birth. It may present in the fetus, infant, or later. Clinical features vary and differ between ...

, which may progress to

neurosyphilis Neurosyphilis is the infection of the central nervous system by '' Treponema pallidum'', the bacterium that causes the sexually transmitted infection syphilis. In the era of modern antibiotics, the majority of neurosyphilis cases have been report ...

if it remains untreated. Protozoa like ''Plasmodium'' or ''Toxoplasma'' which can cause congenital

toxoplasmosis Toxoplasmosis is a parasitic disease caused by ''Toxoplasma gondii'', an apicomplexan. Infections with toxoplasmosis are associated with a variety of neuropsychiatric and behavioral conditions. Occasionally, people may have a few weeks or month ...

with multiple cysts in the brain and other organs, leading to a variety of neurological deficits. Some cases of

schizophrenia Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...

may be related to congenital infections, though the majority are of unknown causes.

Metabolic disorders

Metabolic disorders A metabolic disorder is a disorder that negatively alters the body's processing and distribution of macronutrients, such as proteins, fats, and carbohydrates. Metabolic disorders can happen when abnormal chemical reactions in the body alter the ...

in either the mother or the child can cause neurodevelopmental disorders. Two examples are

diabetes mellitus Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained hyperglycemia, high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or th ...

(a multifactorial disorder) and

phenylketonuria Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. Untreated PKU can lead to intellectual disability, seizures, behavioral problems, and mental disorders. It may also r ...

(an

inborn error of metabolism Inborn errors of metabolism form a large class of genetic diseases involving congenital disorders of enzyme activities. The majority are due to defects of single genes that code for enzymes that facilitate conversion of various substances (substrat ...

). Many such inherited diseases may directly affect the child's

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

and neural development but less commonly they can indirectly affect the child during

gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...

. (See also

teratology Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology caused by ...

). In a child,

type 1 diabetes Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that occurs when the body's immune system destroys pancreatic cells (beta cells). In healthy persons, beta cells produce insulin. Insulin is a hormone require ...

can produce neurodevelopmental damage by the effects of excess or insufficient

glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...

. The problems continue and may worsen throughout childhood if the diabetes is not well controlled.

Type 2 diabetes Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ...

may be preceded in its onset by impaired cognitive functioning. A non-diabetic

fetus A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...

can also be subjected to glucose effects if its mother has undetected

gestational diabetes Gestational diabetes is a condition in which a woman without diabetes develops hyperglycemia, high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms. Obesity increases the rate of pre-eclampsia, cesarea ...

. Maternal diabetes causes excessive birth size, making it harder for the infant to pass through the birth canal without injury or it can directly produce early neurodevelopmental deficits. Usually the neurodevelopmental symptoms will decrease in later childhood.

Phenylketonuria Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. Untreated PKU can lead to intellectual disability, seizures, behavioral problems, and mental disorders. It may also r ...

, also known as PKU, can induce neurodevelopmental problems and children with PKU require a strict diet to prevent intellectual disability and other disorders. In the maternal form of

PKU Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. Untreated PKU can lead to intellectual disability, seizures, behavioral problems, and mental disorders. It may also res ...

, excessive maternal

phenylalanine Phenylalanine (symbol Phe or F) is an essential α-amino acid with the chemical formula, formula . It can be viewed as a benzyl group substituent, substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of ...

can be absorbed by the fetus even if the fetus has not inherited the disease. This can produce intellectual disability and other disorders.

Nutrition

Nutrition disorders and nutritional deficits may cause neurodevelopmental disorders, such as

spina bifida Spina bifida (SB; ; Latin for 'split spine') is a birth defect in which there is incomplete closing of the vertebral column, spine and the meninges, membranes around the spinal cord during embryonic development, early development in pregnancy. T ...

, and the rarely occurring

anencephaly Anencephaly is the absence of a major portion of the brain, skull, and scalp that occurs during embryonic development. It is a cephalic disorder that results from a neural tube defect that occurs when the rostral (head) end of the neural tube ...

, both of which are

neural tube defects Neural tube defects (NTDs) are a group of birth defects in which an opening in the spine or cranium remains from early in human development. In the third week of pregnancy called gastrulation, specialized cells on the dorsal side of the embry ...

with malformation and dysfunction of the

and its supporting structures, leading to serious physical disability and emotional sequelae. The most common nutritional cause of neural tube defects is

folic acid Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and ...

deficiency in the mother, a B vitamin usually found in fruits, vegetables, whole grains, and milk products. (Neural tube defects are also caused by medications and other environmental causes, many of which interfere with folate metabolism, thus they are considered to have multifactorial causes.) Another deficiency,

iodine deficiency Iodine deficiency is a lack of the trace element iodine, an essential nutrient in the diet. It may result in metabolic problems such as goiter, sometimes as an endemic goiter as well as congenital iodine deficiency syndrome due to untreated ...

, produces a spectrum of neurodevelopmental disorders ranging from mild emotional disturbance to severe intellectual disability. (see also

congenital iodine deficiency syndrome Congenital iodine deficiency syndrome (CIDS), also called cretinism, is a medical condition present at birth marked by impaired physical and mental development, due to insufficient thyroid hormone, thyroid hormone production (hypothyroidism) ofte ...

). Excesses in both maternal and infant diets may cause disorders as well, with foods or

food supplement A dietary supplement is a manufactured product intended to supplement a person's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources, or that are synthetic ( ...

s proving toxic in large amounts. For instance in 1973 K.L. Jones and D.W. Smith of the

University of Washington The University of Washington (UW and informally U-Dub or U Dub) is a public research university in Seattle, Washington, United States. Founded in 1861, the University of Washington is one of the oldest universities on the West Coast of the Uni ...

Medical School in

Seattle Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...

found a pattern of "craniofacial, limb, and cardiovascular defects associated with prenatal onset growth deficiency and developmental delay" in children of

alcoholic Alcoholism is the continued drinking of alcohol despite it causing problems. Some definitions require evidence of dependence and withdrawal. Problematic use of alcohol has been mentioned in the earliest historical records. The World Hea ...

mothers, now called

fetal alcohol syndrome Fetal alcohol spectrum disorders (FASDs) are a group of conditions that can occur in a person who is exposed to alcohol during gestation. FASD affects 1 in 20 Americans, but is highly misdiagnosed and underdiagnosed. The several forms of the ...

, It has significant symptom overlap with several other entirely unrelated neurodevelopmental disorders.Fetal alcohol syndrome: guidelines for referral and diagnosis (PDF).
CDC (July 2004). Retrieved on 2007-04-11

Physical trauma

Brain trauma in the developing human is a common cause (over 400,000 injuries per year in the US alone, without clear information as to how many produce developmental sequellae) of neurodevelopmental syndromes. It may be subdivided into two major categories, congenital injury (including injury resulting from otherwise uncomplicated premature birth) and injury occurring in infancy or childhood. Common causes of congenital injury are

asphyxia Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects all the tissues and organs, some more rapidly than others. There are m ...

(obstruction of the

trachea The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from ...

), hypoxia (lack of oxygen to the brain), and the mechanical trauma of the

birth process In probability theory, a birth process or a pure birth process is a special case of a continuous-time Markov process and a generalisation of a Poisson process. It defines a continuous process which takes values in the natural numbers and can only ...

itself.

Placenta

Although it not clear yet as strong is the correlation between

placenta The placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas, and waste exchange between ...

and brain, a growing number of studies are linking placenta to fetal brain development.

Diagnosis

Neurodevelopmental disorders are diagnosed by evaluating the presence of characteristic symptoms or behaviors in a child, typically after a parent, guardian, teacher, or other responsible adult has raised concerns to a doctor. Neurodevelopmental disorders may also be confirmed by

genetic testing Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...

. Traditionally, disease related genetic and genomic factors are detected by karyotype analysis, which detects clinically significant genetic abnormalities for 5% of children with a diagnosed disorder. , chromosomal microarray analysis (CMA) was proposed to replace karyotyping because of its ability to detect smaller chromosome abnormalities and

copy-number variants Copy number variation (CNV) is a phenomenon in which sections of the genome are repeated and the number of repeats in the genome varies between individuals. Copy number variation is a type of structural variation: specifically, it is a type of G ...

, leading to greater diagnostic yield in about 20% of cases. The American College of Medical Genetics and Genomics and the

American Academy of Pediatrics The American Academy of Pediatrics (AAP) is the largest professional association of pediatricians in the United States. It is headquartered in Itasca, Illinois, and maintains an office in Washington, D.C. The AAP has published hundreds of poli ...

recommend CMA as standard of care in the US.

Management

Managing these disorders requires the involvement of professionals. After diagnosis, Parents or caregivers should engage the services of therapists depending on the challenges the individual is faced with, it is also important that they get help, as early intervention can help them overcome these challenges and generally improve their well-being.

References

External links

A Review of Neurodevelopmental Disorders
– Medscape review {{DEFAULTSORT:Neurodevelopmental Disorder Neurological disorders