Macrocephaly-capillary malformation (M-CM) is a multiple malformation syndrome causing body and head overgrowth and abnormalities of the skin, vascular system, brain and limbs. The disorder has recently (June 2012) been attributed to a genetic mutation in a gene called PIK3CA. The mutation in M-CM is thought to always occur after cell division begins and is therefore very unlikely to be inherited. A mutation that happens at this stage results in different percentages of cells being affected in different individuals, so there is significant variability in how severely each individual is affected.
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