Minor physical anomalies

What are minor physical anomalies in schizophrenia?

Minor physical anomalies (MPAs) are subtle anatomical deviations that have little functional or aesthetic impact. They may be traced to events occurring prenatally and may represent risk markers for underlying illness susceptibility. MPAs may be important risk indicators when an individual is already at high risk of developing psychosis, for example, having a first-degree relative with psychosis, and when multiple MPAs occur together in one individual.

What is the evidence for minor physical anomalies in people with schizophrenia?

Moderate to high quality evidence found a large increase in overall MPA scores in people with schizophrenia compared to controls without schizophrenia. There were also increased MPA scores in people with schizophrenia compared to their relatives, with no differences between relatives and controls.

Moderate quality evidence suggests MPA frequency is increased in six regions: head, eyes, ears, mouth, hands and feet. Specific MPAs include tongue with irregular smooth-rough spots, single transverse palmar crease (one crease extending across the palm of the hand), syndactyly (wholly or partially united) 2nd and 3rd toes, malformed ears, low set ears, smaller head circumference, and curved fifth finger.

Moderate to high quality found no differences between people with schizophrenia and controls in second-to-fourth digit ratio, apart from the right hand of males with schizophrenia which showed increased second-to-fourth digit ratio than controls. Second-to-fourth digit ratio is constant throughout life and is the ratio of the length of the index finger (second digit) to the length of the ring finger (fourth digit) of the same hand. Higher 2D:4D ratio is suggested to be the result of lower levels of fetal testosterone.

February 2022

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Last updated at: 5:08 pm, 19th March 2022
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