Discordance for Schimmelpenning–Feuerstein–Mims syndrome in monochorionic twins supports the concept of a postzygotic mutation

Abstract

The Schimmelpenning-Feuerstein-Mims (SFM) syndrome comprises a craniofacial nevus sebaceus, seizures, developmental delay, ocular and skeletal abnormalities. It is a sporadic condition and hypothesized to result from mosaicism involving a lethal autosomal dominant gene. We report a second occurrence of discordant monozygotic (MZ) twins with severe SFM, supporting the concept of a postzygotic mutation.