Probable peripherally associated component of the endosomal sorting required for transport complex III (ESCRT-III) which is involved in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. MVBs contain intraluminal vesicles (ILVs) that are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids (By similarity). Probable peripherally associated component of the endosomal sorting required for transport complex III (ESCRT-III). Reduced cerebellar and forebrain volume. The phenotype of these animals resemble that seen in those after bmi1 knockdown, supporting a link between chmp1a and bmi1. In chmp1a knockdown models, the internal granule and molecular layers were more severely affected than the Purkinje cells, which are consistent with the relatively preserved folia observed in humans with CHMP1A mutations. Belongs to the SNF7 family.