Autosomal recessive primary microcephaly

Autosomal recessive primary microcephaly (MCPH) is a rare genetic disorder in skull growth. Due to gene mutations, especially mitosis in CNS cells is disrupted and patients have a reduced brain size and weight.

At birth, the circumference is reduced by 2 standard deviations (SD), in infants 3 SD and in adults 4 to 12 SD. Depending on the condition, patients suffer from mild to severe mental retardation, which does not increase with age.

In about 10% of those affected, seizures occur. Delayed development may result in speech or movement disturbances, and the body size of those affected may be reduced. Often there are hyperactivity disorders that patients may have a declining forehead.

The brain is proportionately reduced in size with a simplified pattern of gyration. MCPH is inherited as an autosomal recessive trait, and consanguineous (for example, northern Pakistan) has been found to cause increased hives. There is no causal therapy, but the prognosis is generally good.