mosaic variegated aneuploidy syndrome 1
Definition A severe developmental (OMIM:257300) disorder characterised by mosaic aneuploidies (predominantly trisomies and monosomies) involving different chromosomes. Affected individuals typically present with severe intrauterine growth retardation and microcephaly, variably accompanied by ocular defects, mild dysmorphism, developmental delay, other congenital defects, and an increased risk of malignancy, specifically, rhabdomyosarcoma, Wilms tumour and leukaemia.
Molecular pathology Mosaic variegated aneuploidy syndrome 1 is caused by biallelic mutations of BUB1B, which encodes a kinase that is an essential component of the mitotic checkpoint–MC and required for normal mitosis progression. The BUB1B protein product may also play a role in tumour suppression and apoptosis of polyploid cells that exit aberrantly from mitotic arrest.
Synonym MVA syndrome