Autosomal recessive primary microcephaly

Autosomal recessive primary microcephaly (MCPH) is a condition where infants are born with a significantly small head and brain, leading to intellectual disability and developmental delays.

Overview

Autosomal recessive primary microcephaly (MCPH) is a condition in which infants are born with a very small head and a small brain. While the head and brain grow throughout childhood, they remain much smaller than normal.

Symptoms

• Small Head and Brain: Infants have an unusually small head circumference and reduced brain volume compared to peers, though they usually lack major structural brain abnormalities.
• Intellectual and Developmental: Mild to moderate intellectual disability that does not worsen with age. Delayed speech and language skills are common, and motor skills may be mildly delayed.
• Other Features: Some individuals may have a narrow, sloping forehead, mild seizures, attention or behavioral problems, or short stature.

Causes

MCPH can result from mutations in at least seven genes, with ASPM gene mutations being the most common. These genes play vital roles in early brain development by regulating cell division. Mutations impair this process, resulting in fewer nerve cells (neurons) than normal, which leads to the reduced brain and head size.

Inheritance

This condition is inherited in an autosomal recessive pattern. Both copies of the gene in each cell must have mutations for the condition to occur. Parents of an affected individual each carry one copy of the mutated gene but typically do not show signs of the condition.