SNP Shot: Genomic Insights

Microcephaly-capillary malformation syndrome is a genetic condition passed down through families. It is defined by an unusually small head (microcephaly) and capillary malformations, which are abnormalities in the tiny blood vessels near the skin's surface.

In those with this syndrome, microcephaly starts before birth, resulting in a smaller-than-normal brain and various brain abnormalities. Individuals experience frequent, difficult-to-control seizures (intractable epilepsy). These brain development issues and epilepsy cause significant delays in development and intellectual disabilities. Development typically plateaus at the level of a 1- to 2-month-old infant, with most never achieving head control or unassisted sitting.

Capillary malformations appear as pink or red spots on the skin due to enlarged capillaries increasing blood flow. Individuals with microcephaly-capillary malformation syndrome can have anywhere from a few to hundreds of these spots, which can appear anywhere on the body. These spots are generally round or oval, varying in size from pinhead-sized to coin-sized.

Additional symptoms can include unusual movements, problems with feeding, slow growth, and a shorter-than-average height. Finger and toe abnormalities are also common, such as tapered digits and small or missing nails. Some affected children may have characteristic facial features and an atypical pattern of hair growth on their scalp.

Inheritance:

This syndrome follows an autosomal recessive inheritance pattern. This means that a person must inherit two copies of a mutated STAMBP gene, one from each parent, to develop the condition. Typically, parents carrying one copy of the mutated gene do not show symptoms themselves. In rare cases, an individual can inherit both mutated copies of the STAMBP gene from a single parent through a process known as uniparental isodisomy. This occurs due to an error during egg or sperm cell formation.