MCPH1 plays a role at the centrosome via a BRCT1 domain, and in DNA Damage Repair (DDR) via BRCT2 and BRCT3, and it is not clear which of these two mechanisms causes MCPH in man.
Twelve MCPH loci (MCPH1-MCPH12) have been mapped to date from various populations around the world and contain the following genes: Microcephalin, WDR62, CDK5RAP2, CASC5, ASPM, CENPJ, STIL, CEP135, CEP152, ZNF335, PHC1 and CDK6.
Autosomal Recessive Primary Microcephaly (MCPH) is one of those, for which seven loci (MCPH1-MCPH7) with the corresponding genes (MCPH1, WDR62, CDK5RAP2, CEP152, ASPM, CENPJ, and STIL) have been reported so far.
Human autosomal recessive primary microcephaly (MCPH) is a heterogeneous disorder with at least six genetic loci (MCPH1-6), with MCPH5, caused by ASPM mutation, being the most common.
Although genetic heterogeneity for this clinical phenotype had been expected, this has only recently been demonstrated, with the mapping of two loci for autosomal recessive primary microcephaly: MCPH1 at 8p and MCPH2 at 19q.