MedGen

A rare neurological disorder characterized by a reduced head circumference at birth with no gross anomalies of brain structure. It can be an isolated finding or it can be associated with seizures, developmental delay, intellectual disability, balance disturbances, hearing loss or vision problems. [from ORDO]

Autosomal recessive primary microcephaly (MCPH) is a rare genetically heterogeneous disorder of neurogenic brain development with features of reduced head circumference at birth with no gross anomalies of brain architecture and variable degrees of intellectual impairment. It is more common in specific populations, e.g. northern Pakistanis. Consanguinity appears to play a role in incidence. Patients have a reduction in head circumference at birth of at least 2 standard deviations below ethnically matched, age- and sex-related mean values. Caused by mutations in MCPH1, WDR62, CDK5RAP2, CEP152, ASPM, CENPJ, STIL, CEP63, CEP135 , CASC5 and PHC1. These mutations appear to lead to reduced generation of cerebral cortical neurons during embryonic neurogenesis. Inheritance is autosomal recessive. [from SNOMEDCT_US]

Head circumference below 2 standard deviations below the mean for age and gender at birth. [from HPO]

Severe microcephaly and lissencephaly with granular surfaces with immature cortical plate, reduced in thickness, with focal polymicrogyria and immature small neurons with rare processes, intermingled with a considerable number of glial elements. [from HPO]

A group of neural cortical developmental malformations of diverse genetic causes. Clinical manifestations include epilepsy and developmental delays. [from NCI]

An abnormality of the nervous system. [from HPO]

Any autosomal recessive primary microcephaly in which the cause of the disease is a mutation in the PHC1 gene. [from MONDO]

MCPH causes intellectual disability, which is typically mild to moderate and does not become more severe with age. Most affected individuals have delayed speech and language skills. Motor skills, such as sitting, standing, and walking, may also be mildly delayed.

People with MCPH usually have few or no other features associated with the condition. Some have a narrow, sloping forehead; mild seizures; problems with attention or behavior; or short stature compared to others in their family. The condition typically does not affect any other major organ systems or cause other health problems.

Infants with MCPH have an unusually small head circumference compared to other infants of the same sex and age. Head circumference is the distance around the widest part of the head, measured by placing a measuring tape above the eyebrows and ears and around the back of the head. Affected infants' brain volume is also smaller than usual, although they usually do not have any major abnormalities in the structure of the brain. The head and brain grow throughout childhood and adolescence, but they continue to be much smaller than normal.

Autosomal recessive primary microcephaly (often shortened to MCPH, which stands for "microcephaly primary hereditary") is a condition in which infants are born with a very small head and a small brain. The term "microcephaly" comes from the Greek words for "small head." [from MedlinePlus Genetics]