Mosaic Variegated Aneuploidy Syndrome 1; MVA1
OMIM number: 257300
Comments closing date: 09/12/2025
Mosaic Variegated Aneuploidy Syndrome 1 (MVA1) is a rare inherited condition that affects how cells divide and grow. In people with MVA1, some cells end up with the wrong number of chromosomes. Because this happens unevenly across the body, it’s called “mosaic,” and the mix of extra or missing chromosomes is called “variegated aneuploidy.” Children with MVA1 often have slow growth before and after birth, a small head size, and distinctive facial features. They may experience delays in learning and development, and sometimes have problems with their eyes or brain structure. One of the most
serious concerns is a higher risk of developing certain childhood cancers, such as kidney or muscle tumors. MVA1 is passed down when both parents carry a faulty version of a gene called BUB1B, which helps cells divide properly. Although the condition is very rare, understanding it can help families get the right medical care and support. Doctors may monitor children with MVA1 closely to catch any complications early and provide therapies to help with development and health.
