Mosaic Variegated Aneuploidy Syndrome

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Mosaic variegated aneuploidy (MVA) syndrome is a rare disorder in which some cells in the body have an abnormal number of chromosomes instead of the usual 46 chromosomes, a situation known as aneuploidy. Most commonly, cells have an extra chromosome, which is called trisomy, or are missing a chromosome, which is known as monosomy. In MVA syndrome, some cells are aneuploid and others have the normal number of chromosomes, which is a phenomenon known as mosaicism. Typically, at least one-quarter of cells in affected individuals have an abnormal number of chromosomes. Because the additional or missing chromosomes vary among the abnormal cells, the aneuploidy is described as variegated.

BUB1B gene mutations cause MVA syndrome type 1, CEP57 gene mutations cause MVA syndrome type 2, and TRIP13 gene mutations cause the other form of MVA syndrome. Some people with MVA syndrome do not have mutations in any of these genes. Other genes that have not been identified are likely also involved in the condition.

MVA syndrome is a rare condition. Its prevalence is unknown.

All types of MVA syndrome are inherited in an autosomal recessive pattern, which means both copies of the BUB1B, CEP57, or TRIP13 gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Published Date: July 01, 2017
Published By: National Institutes of Health