Megalencephaly and perisylvian polymicrogyria with postaxial polydactyly and hydrocephalus (MPPH): report of a new case.

Megalencephaly (MEG), or enlargement of the brain, can either represent a familial variant with normal cerebral structure, or a rare brain malformation associated with developmental delay and neurological problems. MEG has been split into two subtypes: anatomical and metabolic. The latter features a build-up inside the cells owing to metabolic causes. Anatomical MEG has been detected in many different conditions, including many overgrowth syndromes. In 2004 Mirzaa et al. reported five non-consanguineous patients with a new MCA/MR syndrome characterized by severe congenital MEG with polymicrogyria (PMG), postaxial polydactyly (POLY) and hydrocephalus (HYD). The authors argued that these findings identified a new and distinct malformation syndrome, which they named MPPH. We report on a new case of MPPH, the first to be described after the original series (Mirzaa et al., 2004).