Brachycephaly (derived from the Ancient Greek '' βραχύς'', 'short' and '' κεφαλή'', 'head') is the shape of a skull shorter than average in its species. It is perceived as a cosmetically desirable trait in some domesticated dog and cat breeds, notably the pug and Persian, and can be normal or abnormal in other animal species. In humans, brachycephaly can appear both pathologically and non-pathologically as a result of normal human variation. It is particularly common in Mongolians and the Andamanese. In anthropology, human populations have been characterized as either dolichocephalic (long-headed), mesocephalic (moderate-headed), or brachycephalic (short-headed). The usefulness of the cephalic index was questioned by

Giuseppe Sergi Giuseppe Sergi (March 20, 1841 – October 17, 1936) was an Italian anthropologist of the early twentieth century, best known for his opposition to Nordicism in his books on the racial identity of Mediterranean peoples. He rejected existing racia ...

, who argued that cranial morphology provided a better means to model racial ancestry. When pathological, it is known as flat head syndrome, and it results from premature fusion of the coronal sutures, or from external deformation. The coronal suture is the fibrous joint that unites the frontal bone with the two parietal bones of the skull. The parietal bones form the top and sides of the skull. This feature can also be a symptom of Down syndrome. There are also cases of brachycephaly associated with plagiocephaly. Brachycephaly with plagiocephaly is positional and has become more prevalent since the "Back to Sleep" campaign. The Back to Sleep campaign began in 1994 as a way to educate parents about ways to reduce the risk for sudden infant death syndrome (SIDS). The campaign was named for its recommendation to place healthy babies on their backs to sleep. Placing babies on their backs to sleep reduces the risk for SIDS, also known as "cot death" or "crib death." This campaign has been successful in promoting infant back sleeping and other risk-reduction strategies to parents, family members, child care providers, health professionals, and all other caregivers of infants, at the cost of increasing the incidence of this deformation of the head. It is considered a cosmetic problem. Many pediatricians remain unaware of the issue and possible treatments. Treatments include regular prone repositioning of babies ("

tummy time Tummy time is a colloquialism for placing infants in the prone position while awake and supervised, to encourage development of the neck and Thorax, trunk muscles and prevent Plagiocephaly, skull deformations. In 1992, the American Academy of Pe ...

").

Brachycephaly as a trait in pets

In pets, brachycephaly describes a type of skull with a high cephalic index, such as in snub-nosed breeds of dog such as pugs, Shih Tzus, and bulldogs or cats such as the Persian,

Exotic Exotic may refer to: Mathematics and physics * Exotic R4, a differentiable 4-manifold, homeomorphic but not diffeomorphic to the Euclidean space R4 * Exotic sphere, a differentiable ''n''-manifold, homeomorphic but not diffeomorphic to the ordina ...

and Himalayan. The term is from Greek roots meaning 'short' and 'head'. While being a cosmetically desirable trait of specific cat and dog breeds, the production and breeding of brachycephalic animals is considered animal abuse in a few jurisdictions. Due to the fact that animals with significantly shortened skulls frequently develop brachycephalic airway obstructive syndrome, causing them to have difficulties when breathing, suffering from hyperthermia due to insufficient cooling abilities and frequent infections of the cornea and lacrimal glands. While the breeding of animals that will have significantly worsened life quality due to anatomical abnormalities is illegal in some European countries, the production of such breeds is still frequent. Apart from these, brachycephalic pups and kittens also have high prenatal mortality. Attention should be paid to breed standards which promote increased brachycephaly in cats which has the potential to negatively impact their welfare, and potential buyers of brachycephalic cat breeds should be made aware of the risks of their conformation. Brachycephalic cat breeds such as the

Burmese Burmese may refer to: * Something of, from, or related to Myanmar, a country in Southeast Asia * Burmese people * Burmese language * Burmese alphabet * Burmese cuisine * Burmese culture Animals * Burmese cat * Burmese chicken * Burmese (hor ...

, Himalayan and Persian normally have mandibular mesioclusion — a condition involving the incisors not being aligned correctly. This can lead to the incisors injuring the gingival tissue. In mesaticephalic breeds this is considered abnormal.

Diagnosis

Conditions with brachycephaly

* Achard syndrome * Achondrogenesis type II * Acrocephalosyndactyly type I *

Acrodysostosis Acrodysostosis is a rare congenital malformation syndrome which involves shortening of the interphalangeal joints of the hands and feet, intellectual disability in approximately 90% of affected children, and peculiar facies. Other common abnor ...

1 with or without hormone resistance * Acrofrontofacionasal dysostosis * Acromelic frontonasal dysostosis * Acyl-CoA oxidase deficiency *

Adenylosuccinate lyase deficiency Adenylosuccinate lyase deficiency is a rare autosomal recessive metabolic disorder characterized by the appearance of succinylaminoimidazolecarboxamide riboside (SAICA riboside) and succinyladenosine (S-Ado) in cerebrospinal fluid, urine. These t ...

* Agenesis of the corpus callosum with peripheral neuropathy *

ALDH18A1 Delta-1-pyrroline-5-carboxylate synthetase (P5CS) is an enzyme that in humans is encoded by the ''ALDH18A1'' gene. This gene is a member of the aldehyde dehydrogenase family and encodes a bifunctional ATP- and NADPH-dependent mitochondrial enzym ...

-related

de Barsy syndrome De Barsy syndrome is a rare autosomal recessive genetic disorder. Symptoms include cutis laxa (loose hanging skin) as well as other eye, musculoskeletal, and neurological abnormalities. It is usually progressive, manifesting side effects that can ...

* ALG9 congenital disorder of

glycosylation Glycosylation is the reaction in which a carbohydrate (or ' glycan'), i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule (a glycosyl acceptor) in order to form a glycoconjugate. In biology (but not al ...

Alveolar capillary dysplasia Alveolar capillary dysplasia (ACD) is a rare, congenital diffuse lung disease characterized by abnormal blood vessels in the lungs that cause highly elevated pulmonary blood pressure and an inability to effectively oxygenate and remove carbon ...

with pulmonary venous misalignment *

Angelman syndrome Angelman syndrome or Angelman's syndrome (AS) is a genetic disorder that mainly affects the nervous system. Symptoms include a small head and a specific facial appearance, severe intellectual disability, developmental disability, limited to no f ...

* Antley-Bixler syndrome * Aspartylglucosaminuria * Autism spectrum disorder due to

AUTS2 AUTS2, activator of transcription and developmental regulator is a protein that in humans is encoded by the AUTS2 gene. Function This gene has been implicated in neurodevelopment and as a candidate gene for numerous neurological disorders, in ...

deficiency * Autosomal recessive faciodigitogenital syndrome * Axenfeld-Rieger anomaly * Bailey-Bloch congenital myopathy * Bardet-Biedl syndrome * CHIME syndrome * Cleidocranial dysplasia, recessive form * Coffin-Siris syndrome * Complete trisomy 21 syndrome * Complex lethal osteochondrodysplasia * Congenital contractural arachnodactyly * Congenital disorder of

, type iit * Congenital heart defects and ectodermal dysplasia *

Cornelia de Lange syndrome Cornelia de Lange syndrome (CdLS) is a genetic disorder. People with this syndrome experience a range of physical, cognitive, and medical challenges ranging from mild to severe. The syndrome has a widely varied phenotype, meaning people with the sy ...

* Craniofacial dysplasia- osteopenia syndrome * Craniofrontonasal syndrome * Craniosynostosis-anal anomalies-porokeratosis syndrome *

Crouzon syndrome Crouzon syndrome is an autosomal dominant genetic disorder known as a branchial arch syndrome. Specifically, this syndrome affects the first branchial (or pharyngeal) arch, which is the precursor of the maxilla and mandible. Since the branchial ...

* Crouzon syndrome-acanthosis nigricans syndrome * DeSanto-Shinawi syndrome due to WAC point mutation * Ehlers-Danlos syndrome * Fine-Lubinsky syndrome * Fontaine

progeroid syndrome Progeroid syndromes (PS) are a group of rare genetic disorders that mimic physiological aging, making affected individuals appear to be older than they are. The term ''progeroid syndrome'' does not necessarily imply progeria (Hutchinson–Gilford ...

* Frank-Ter Haar syndrome * Frontonasal dysplasia-severe

microphthalmia Microphthalmia (Greek: grc, μικρός, mikros, small, label=none, grc, ὀφθαλμός, ophthalmos, eye, label=none, also referred as microphthalmos, is a developmental disorder of the eye in which one (unilateral microphthalmia) or both ( ...

-severe facial clefting syndrome * Frontonasal dysplasia with alopecia and genital anomaly * Gomez-Lopez-Hernandez syndrome * Hallermann-Streiff syndrome * Hereditary spastic paraplegia * Hirsutism- skeletal dysplasia- intellectual disability syndrome * Holoprosencephaly, recurrent infections, and monocytosis * Infantile hypotonia, with

psychomotor retardation Psychomotor may refer to: * Psychomotor learning, the relationship between cognitive functions and physical movement * Psychomotor retardation, a slowing-down of thought and a reduction of physical movements in an individual * Psychomotor agitatio ...

and characteristic

facies In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with specified characteristics, which can be any observable attribute of rocks (such as their overall appearance, composition, or condition of formatio ...

* Intellectual disability- facial dysmorphism syndrome due to

SETD5 SET domain containing 5 is a protein that in humans is encoded by the SETD5 gene. It is a member of the histone lysine methyltransferase family. Overexpression of SETD5 is associated positively with progression of breast cancer. Mutations in SE ...

haploinsufficiency * Intellectual disability- microcephaly- strabismus- behavioral abnormalities syndrome *

KBG syndrome KBG syndrome is a rare genetic disease that is the result of a mutation in the ANKRD11 gene at location 16q24.3. Only about a hundred known cases have been reported, although it is expected to be under-reported. The syndrome was first described b ...

* Kleefstra syndrome * Kohlschutter-Tonz syndrome-like * Larsen-like syndrome, B3GAT3 type * Lethal occipital

encephalocele Encephalocele is a neural tube defect characterized by sac-like protrusions of the brain and the membranes that cover it through openings in the skull. These defects are caused by failure of the neural tube to close completely during fetal develop ...

- skeletal dysplasia syndrome * Lethal

osteosclerotic Osteosclerosis is a disorder that is characterized by abnormal hardening of bone and an elevation in bone density. It may predominantly affect the medullary portion and/or cortex of bone. Plain radiographs are a valuable tool for detecting and ...

bone dysplasia *

Mandibuloacral dysplasia Mandibuloacral dysplasia (MAD) is a rare autosomal recessive syndrome characterized by mandibular hypoplasia, delayed cranial suture closure, dysplastic clavicles, abbreviated and club-shaped terminal phalanges, acroosteolysis, atrophy of the skin ...

* MEGF8-related Carpenter syndrome * Methylmalonic acidemia with homocystinuria, type cblX *

MGAT2 Alpha-1,6-mannosyl-glycoprotein 2-beta-N-acetylglucosaminyltransferase is an enzyme that in humans is encoded by the ''MGAT2'' gene. The product of this gene is a Golgi enzyme catalyzing an essential step in the conversion of oligomannose to comp ...

-congenital disorder of

Micro Micro may refer to: Measurement * micro- (μ), a metric prefix denoting a factor of 10−6 Places * Micro, North Carolina, town in U.S. People * DJ Micro, (born Michael Marsicano) an American trance DJ and producer *Chii Tomiya (都宮ちい ...

brachycephaly-

ptosis Ptosis (from the Greek: πτῶσις 'falling', 'a fall', 'dropped') refers to droopiness or abnormal downward displacement of a body part or organ. Particular cases include: * Ptosis (eyelid) * Ptosis (chin) * Ptosis (breasts) * Visceroptosis, ...

- cleft lip syndrome * Microcephaly, facial dysmorphism,

renal agenesis Renal agenesis is a medical condition in which one (unilateral) or both (bilateral) fetal kidneys fail to develop. Unilateral and bilateral renal agenesis in humans, mice and zebra fish has been linked to mutations in the gene GREB1L. It has also ...

, and

ambiguous genitalia Intersex people are individuals born with any of several sex characteristics including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical bina ...

syndrome *

Microphthalmia Microphthalmia (Greek: grc, μικρός, mikros, small, label=none, grc, ὀφθαλμός, ophthalmos, eye, label=none, also referred as microphthalmos, is a developmental disorder of the eye in which one (unilateral microphthalmia) or both ( ...

with brain and digit anomalies * MOMO syndrome * Muenke syndrome * Neonatal pseudo-

hydrocephalic Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull. Older people may have headaches, double vision, poor balance, urinary incon ...

* Oculodentodigital dysplasia, autosomal recessive * Osteogenesis imperfecta * Osteosclerosis, Stanescu type * Phosphoribosylaminoimidazole carboxylase deficiency * Pontocerebellar hypoplasia * Potocki-Shaffer syndrome * RAB23-related Carpenter syndrome * Radial aplasia- thrombocytopenia syndrome * Renpenning syndrome * Ritscher-Schinzel syndrome * Saethre-Chotzen syndrome * Smith-Magenis syndrome * Spastic paraplegia, intellectual disability, nystagmus, and obesity *

Spondyloepimetaphyseal dysplasia Spondyloepimetaphyseal dysplasia is a genetic condition affecting the bones. Types include: * Spondyloepimetaphyseal dysplasia, Strudwick type * Spondyloepiphyseal dysplasia congenita * Spondyloepimetaphyseal dysplasia, Pakistani type References ...

, Genevieve type *

SRD5A3 Steroid 5-alpha-reductase 3, also known as 3-oxo-5-alpha-steroid 4-dehydrogenase 3, is an enzyme that in humans is encoded by the ''SRD5A3'' gene. It is one of three forms of 5α-reductase. See also * SRD5A3-CDG * Congenital disorder of glycosyl ...

-congenital disorder of

* Trigonocephaly-bifid nose-acral anomalies syndrome * Weill-Marchesani syndrome Apert Syndrome 5.jpg, Apert syndrome Carpenter Syndrome 2.jpg, Carpenter syndrome Microcephalus A (side).jpg, Microcephaly Lewin Acrocephaly 2.jpg, Pfeiffer syndrome Coats Oxycephaly 1.jpg, Saethre-Chotzen syndrome

Treatment

In humans, brachycephaly can be corrected with cranial remolding orthoses (helmets), which provide painless total contact over the prominent areas of the skull and leave voids over the flattened areas to provide a pathway for more symmetrical skull growth. Treatment generally takes 3–4 months, but varies depending on the infant's age and the severity of the cranial asymmetry. However, studies by scientists in the Netherlands investigating helmet therapy on mild to moderate cases of brachycephaly have found there was no significant difference over time between infants treated with helmets and infants left untreated. All parents of infants treated with helmets confirmed negative side effects including skin irritation and sweating. The study was criticised by the American Orthotic & Prosthetic Association in a letter to the ''New York Times''. The letter noted that the study focused only on mild to moderate cases, saying that helmet treatment may still be useful for more severe cases. The letter also criticised the low participation rate (21%) of the randomized study, and noted that the incidence of fitting issues in the study, at 73%, "seems very high".

References

External links

NINDS – Cephalic Disorders Overview

Brachycephalic Official Website

{{Congenital malformations and deformations of musculoskeletal system Congenital disorders of musculoskeletal system Hereditary dog diseases