Microhydranencephaly is a developmental abnormality that affects the brain. Signs and symptoms may include extreme microcephaly, scalp rugae (a series of ridges), profound developmental delay and severe intellectual disability. Imaging studies of the brain generally reveal incomplete brain formation and severe hydrocephalus (accumulation of fluid in the brain). In most cases, the underlying cause is unknown. Rarely, the condition is caused by changes (mutations) in the NDE1 gene and is inherited in an autosomal recessive manner. Treatment is based on the signs and symptoms present in each person.

NDE1 gene. In these rare cases, more than one family member (often a pair of siblings) had the condition.

and not be a carrier.

A diagnosis of microhydranencephaly is generally suspected based on the presence of characteristic signs and symptoms. Additional testing can then be ordered to confirm the diagnosis. This generally consists of imaging studies to evaluate the brain for structural abnormalities and severe hydrocephalus (accumulation of fluid in the brain).