CHMP1A and hereditary disease: Against the background of the multiplicity of functions ascribed to ESCRT-III, it is perhaps surprising that only three complex members, CHMP1A, CHMP2B, and CHMP4B, have been implicated in Mendelian genetic disease thus far.17, 18, 19 This may be explained by functional redundancy between ESCRT-III complex components, or because loss of components might lead to an embryonic lethal phenotype, as has been observed in some, but not all, mouse models lacking specific CHMP proteins.57