Clinical Guidance
MPPH syndrome is a developmental brain disorder characterized by megalencephaly (brain overgrowth) with the cortical malformation bilateral perisylvian polymicrogyria. To date, fewer than than 100 individuals with features of MPPH syndrome have been reported with either a clinical diagnosis (presence of the 2 core clinical and imaging findings: megalencephaly and polymicrogyria) , and/or a molecularly confirmed diagnosis [, , , , , , , , , , , , , , , , , , , ]. Table 2. MPPH Syndrome: Frequency of Select Features
Feature | % of Persons w/Feature | Comment |
|---|
Megalencephaly | 100% | — |
Cortical malformations | 100% | Typically BPP but other types of PMG have also been seen |
Hydrocephalus | ~50% | Ventriculomegaly seen in most individuals |
Oromotor dysfunction | ~50% | Specifically assoc w/BPP |
Hypotonia | ~80% | — |
Epilepsy | ~100% | — |
Intellectual disability | 100% | — |
Postaxial polydactyly | 50% | BPP = bilateral perisylvian polymicrogyria; PMG = polymicrogyria Megalencephaly (brain overgrowth). Most individuals with MPPH syndrome reported to date have congenital or early postnatal megalencephaly (i.e., rapidly progressive megalencephaly within the first year of life). |
Source: GeneReviews — "MPPH Syndrome"
