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Pentasomy X
Pentasomy X, also known as 49,XXXXX, is a chromosomal disorder in which a female has five, rather than two, copies of the X chromosome. Pentasomy X is associated with short stature, intellectual disability, characteristic facial features, heart defects, skeletal anomalies, and pubertal and reproductive abnormalities. The condition is exceptionally rare, with an estimated prevalence between 1 in 85,000 and 1 in 250,000. The condition has a large variety of symptoms, and it is difficult to paint a conclusive portrait of its phenotypes. Though significant disability is characteristic, there are so few diagnosed cases that confident conclusions about the presentation and prognosis remain impossible. Pentasomy X may be mistaken for more common chromosomal disorders, such as Down syndrome or Turner syndrome, before a conclusive diagnosis is reached. Pentasomy X is not inherited but rather occurs via nondisjunction, a random event in gamete development. In rare cases, it may be rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nondisjunction
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division (mitosis/meiosis). There are three forms of nondisjunction: failure of a pair of homologous chromosomes to separate in meiosis I, failure of sister chromatids to separate during meiosis II, and failure of sister chromatids to separate during mitosis. Nondisjunction results in daughter cells with abnormal chromosome numbers (aneuploidy). Calvin Bridges and Thomas Hunt Morgan are credited with discovering nondisjunction in ''Drosophila melanogaster'' sex chromosomes in the spring of 1910, while working in the Zoological Laboratory of Columbia University. Proof of the chromosome theory of heredity emerged from these early studies of chromosome non-disjunction. Types In general, nondisjunction can occur in any form of cell division that involves ordered distribution of chromosomal material. Higher animals have three distinct forms of such cell divisions: Meiosis I and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inclusion (education)
Inclusion in education refers to including all students to equal access to equal opportunities of education and learning, and is distinct from educational equality or educational equity. It arose in the context of special education with an individualized education program or 504 plan, and is built on the notion that it is more effective for students with special needs to have the said mixed experience for them to be more successful in social interactions leading to further success in life. The philosophy behind the implementation of the inclusion model does not prioritize, but still provides for the utilization of special classrooms and special schools for the education of students with disabilities. Inclusive education models are brought into force by educational administrators with the intention of moving away from seclusion models of special education to the fullest extent practical, the idea being that it is to the social benefit of general education students and specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hip Dysplasia
Hip dysplasia is an abnormality of the hip joint where the socket portion does not fully cover the ball portion, resulting in an increased risk for joint dislocation. Hip dysplasia may occur at birth or develop in early life. Regardless, it does not typically produce symptoms in babies less than a year old. Occasionally one leg may be shorter than the other. The left hip is more often affected than the right. Complications without treatment can include arthritis, limping, and low back pain. Females are affected more often than males. Risk factors for hip dysplasia include female sex, family history, certain swaddling practices, and breech presentation whether an infant is delivered vaginally or by cesarean section. If one identical twin is affected, there is a 40% risk the other will also be affected. Screening all babies for the condition by physical examination is recommended. Ultrasonography may also be useful. Many of those with mild instability resolve without specific t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypotonia
Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but it is a potential manifestation of many different diseases and disorders that affect motor nerve control by the brain or muscle strength. Hypotonia is a lack of resistance to passive movement whereas muscle weakness results in impaired active movement. Central hypotonia originates from the central nervous system, while peripheral hypotonia is related to problems within the spinal cord, peripheral nerves, and/or skeletal muscles. Severe hypotonia in infancy is commonly known as floppy baby syndrome. Recognizing hypotonia, even in early infancy, is usually relatively straightforward, but medical diagnosis, diagnosing the underlying cause can be difficult and often unsuccessful. The long-term effects of hypotonia on a child's development and later life depend primarily on the severity of the mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Deviation
In statistics, the standard deviation is a measure of the amount of variation of the values of a variable about its Expected value, mean. A low standard Deviation (statistics), deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the values are spread out over a wider range. The standard deviation is commonly used in the determination of what constitutes an outlier and what does not. Standard deviation may be abbreviated SD or std dev, and is most commonly represented in mathematical texts and equations by the lowercase Greek alphabet, Greek letter Sigma, σ (sigma), for the population standard deviation, or the Latin script, Latin letter ''s'', for the sample standard deviation. The standard deviation of a random variable, Sample (statistics), sample, statistical population, data set, or probability distribution is the square root of its variance. (For a finite population, v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrasomy X
Tetrasomy X, also known as 48,XXXX, is a chromosomal disorder in which a female has four, rather than two, copies of the X chromosome. It is associated with intellectual disability of varying severity, characteristic "coarse" facial features, heart defects, and skeletal anomalies such as increased height, clinodactyly (incurved pinky fingers), and radioulnar synostosis (fusion of the long bones in the forearm). Tetrasomy X is a rare condition, with few medically recognized cases; it is estimated to occur in approximately 1 in 50,000 females. The disorder has a wide range of symptoms, with phenotypes (presentations) ranging from slight to severe. It is suspected to be underdiagnosed, as are other sex chromosome disorders. Life outcomes vary; some women have had education, employment, and children, while others have remained dependent into adulthood. Life expectancy does not appear to be substantially reduced. Tetrasomy X has phenotypic overlap with a number of more common di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facies (medical)
In medical contexts, a facies is a distinctive facial expression or appearance associated with a specific medical condition. The term comes from Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ... for "face". As a fifth declension noun, ''facies'' can be both singular and plural. Types Examples include: * Hippocratic facies – eyes are sunken, temples collapsed, nose is pinched with crusts on the lips, and the forehead is clammy * Moon face (also known as "Cushingoid facies") – Cushing's syndrome * Elfin facies – Williams syndrome, Donohue syndrome * Potter facies – oligohydramnios * Mask like facies – parkinsonism * Leonine facies – lepromatous leprosy or craniometaphyseal dysplasia * Mitral facies – mitral stenosis * Amiodarone facies (deep blu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicanthic Folds
An epicanthic fold or epicanthus is a skin fold of the upper eyelid that covers the inner corner (medial canthus) of the eye. However, variation occurs in the nature of this feature and the presence of "partial epicanthic folds" or "slight epicanthic folds" is noted in the relevant literature. Various factors influence whether epicanthic folds form, including ancestry, age, and certain medical conditions. The primary cause of the epicanthic fold is the hypertrophy of the preseptal portion of the orbicularis oculi muscle. Etymology ''Epicanthus'' means 'above the canthus', with epi-canthus being the Latinized form of the Ancient Greek : 'corner of the eye'. Classification Variation in the shape of the epicanthic fold has led to four types being recognised: * ''Epicanthus supraciliaris'' runs from the brow, curving downwards towards the lachrymal sac. * ''Epicanthus palpebralis'' begins above the upper tarsus and extends to the inferior orbital rim. * ''Epicanthus tarsa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertelorism
Hypertelorism is an abnormally increased distance between two organs or bodily parts, usually referring to an increased distance between the orbits (eyes), or orbital hypertelorism. In this condition, the distance between the inner eye corners, as well as the distance between the pupils, is greater than normal. Hypertelorism should not be confused with telecanthus, in which the distance between the inner eye corners is increased, but the distances between the outer eye corners and the pupils remain unchanged.Michael L. Bentz: ''Pediatric Plastic Surgery''; Chapter 9 Hypertelorism by Renato Ocampo, Jr., MD/ John A. Persing, MD Hypertelorism is a symptom in a variety of syndromes, including Edwards syndrome (trisomy 18), 1q21.1 duplication syndrome, basal cell nevus syndrome, DiGeorge syndrome and Loeys–Dietz syndrome. Hypertelorism can also be seen in Apert syndrome, Autism spectrum disorder, craniofrontonasal dysplasia, Noonan syndrome, neurofibromatosis, LEOPARD syndrome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-set Ears
Low-set ears are a clinical feature in which the ears are positioned lower on the head than usual. They are present in many congenital conditions. Low-set ears are defined as the outer ears being positioned two or more standard deviations lower than the population average. Clinically, if the point at which the helix (curved upper part) of the outer ear meets the cranium is at or below the line connecting the inner canthi of eyes (the bicanthal plane), the ears are considered low set. Low-set ears can be associated with conditions such as: * Down syndrome *Turner syndrome *Noonan syndrome Noonan syndrome (NS) is a genetic disorder that may present with mildly unusual facial features, short height, congenital heart disease, bleeding problems, and skeletal malformations. Facial features include widely spaced eyes, light-colored ... *Patau syndrome *DiGeorge syndrome *Cri du chat syndrome *Edwards syndrome *Fragile X syndrome *Okamoto syndrome It is usually Bilateral symmet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcephaly
Microcephaly (from Neo-Latin ''microcephalia'', from Ancient Greek μικρός ''mikrós'' "small" and κεφαλή ''kephalé'' "head") is a medical condition involving a smaller-than-normal head. Microcephaly may be present at birth or it may develop in the first few years of life. Brain development is often affected; people with this disorder often have an intellectual disability, poor motor function, poor speech, abnormal facial features, seizures and dwarfism. The disorder is caused by a disruption to the genetic processes that form the brain early in pregnancy, though the cause is not identified in most cases. Many genetic syndromes can result in microcephaly, including chromosomal and single-gene conditions, though almost always in combination with other symptoms. Mutations that result solely in microcephaly (primary microcephaly) exist but are less common. External toxins to the embryo, such as alcohol during pregnancy or vertically transmitted infections, can a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinky Finger
The little finger or pinkie, also known as the baby finger, fifth digit, or pinky finger, is the most ulnar and smallest digit of the human hand, and next to the ring finger. Etymology The word "pinkie" is derived from the Dutch word ''pink'', meaning "little finger". The earliest recorded use of the term "pinkie" is from Scotland in 1808. The term (sometimes spelled "pinky") is common in Scottish English and American English, and is also used extensively in other Commonwealth countries such as New Zealand, Canada, and Australia. Nerves and muscles There are nine muscles that control the fifth digit: Three in the hypothenar eminence, two extrinsic flexors, two extrinsic extensors, and two more intrinsic muscles: * Hypothenar eminence: ** Opponens digiti minimi muscle ** Abductor minimi digiti muscle (adduction from third palmar interossei) ** Flexor digiti minimi brevis (the "longus" is absent in most humans) * Two extrinsic flexors: ** Flexor digitorum superficialis ** F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
