Pontocerebellar hypoplasia (PCH) represents a heterogeneous group of disorders characterized by an abnormally small cerebellum and brainstem. Pontocerebellar hypoplasia type 4 (PCH4) is characterized by severe course and early lethality ({2:Budde et al., 2008}). For a phenotypic description and a discussion of genetic heterogeneity of PCH, see PCH1 ({607596}).