Minor physical anomalies (MPAs) are relatively minor (typically painless and, in themselves, harmless) congenital physical abnormalities consisting of features such as

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 outer ears positioned two or more standard deviations lower than the p ...

telecanthus Telecanthus, or dystopia canthorum, refers to increased distance between the inner corners of the eyelids (medial canthi), while the inter-pupillary distance is normal. This is in contrast to hypertelorism, in which the distance between the w ...

, micrognathism,

macrocephaly Macrocephaly is a condition in which circumference of the human head is abnormally large. It may be pathological or harmless, and can be a familial genetic characteristic. People diagnosed with macrocephaly will receive further medical tests to ...

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 a potential manifestation of many different diseases ...

and furrowed tongue. While MPAs may have a genetic basis, they might also be caused by factors in the fetal environment: anoxia, bleeding, or

infection An 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 dis ...

. MPAs have been linked to disorders of

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

and are thought by some to be a marker for insults to the fetal neural development towards the end of the first trimester. Thus, in the neurodevelopmental literature, they are seen as indirect indications of interferences with

brain development 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 fiel ...

. MPAs have been studied in autism,

Down syndrome Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual dis ...

, and in

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wit ...

. A 2008

meta-analysis A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Meta-analyses can be performed when there are multiple scientific studies addressing the same question, with each individual study reporting me ...

found that MPAs are significantly increased in the autistic population. A 1998 study found that 60% of its schizophrenic sample and 38% of their siblings had 6 or more MPAs (especially in the

craniofacial Craniofacial (''cranio-'' combining form meaning head or skull + ''-facial'' combining form referring to the facial structures grossly) is an adjective referring to the parts of the head enclosing the brain and the face. The term is typically used ...

area), while only 5% of the control group showed that many. The most often cited MPA, high arched palate, is described in articles as a microform of a

cleft palate A cleft lip contains an opening in the upper lip that may extend into the nose. The opening may be on one side, both sides, or in the middle. A cleft palate occurs when the palate (the roof of the mouth) contains an opening into the nose. The ...

. Cleft palates are partly attributable to hypoxia. The vaulted palate caused by nasal obstruction and consequent mouth breathing, without the lateralising effect of the tongue, can produce hypoxia at night. Other MPAs are reported only sporadically. Capillary malformation is induced by RASA1 mutation and can be changed by hypoxia. A study in the ''American Journal of Psychiatry'' by Trixler et al.: found hemangiomas to be highly significant in schizophrenia.

Exotropia Exotropia is a form of strabismus where the eyes are deviated outward. It is the opposite of esotropia and usually involves more severe axis deviation than exophoria. People with exotropia often experience crossed diplopia. Intermittent exotrop ...

is reported as having low correlation and high significance as well. It can be caused by perinatal hypoxia.R. Huo, S.K. Burden, C.S. Hoyt and W.V. Good; "Chronic cortical visual impairment in children: aetioloy, prognosis and associated neurological deficits"; The British Journal of Ophthalmology r J Ophthalmol 1999 Jun; Vol. 83 (6).

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Further reading