A Female Patient with FMR1 Premutation and Mosaic X Chromosome Aneuploidy and Two Sons with Intellectual Disability.

In this report, we describe a molecular cytogenetic study of a family burdened with intellectual disability (ID) and suicide. Our study revealed that the mother has a heterozygous premutation in the FMR1 gene and supernumerary X chromosomes as well as X-derived marker chromosomes. Both of her sons have ID and a normal chromosome number. One of the sons has fragile X syndrome, and the other has ID of an unclear nature.