Co-occurrence of multiple sclerosis and cancer in a BRCA1 positive family.

Multiple sclerosis is not known to be a risk factor for subsequent development of cancer. Recently, a multiple sclerosis locus was mapped adjacent to BRCA1 gene. We present a familial case affected by multiple sclerosis and cancer. We identified a c.5266dupC (5382insC) frameshift mutation in a 33-year-old woman with breast cancer, multiple malignant melanomas and multiple sclerosis. The patient's family history shows further cases of multiple sclerosis in BRCA1 mutation carriers. Therefore the presented family may carry a monogenic predisposition for multiple sclerosis nearby to BRCA1.