Incontinentia pigmenti, a chromosomal instability syndrome, is associated with childhood malignancy

Incontinentia pigmenti (IP) is a rare hereditary disorder that has recently been classified as a chromosomal instability syndrome. As in Fanconi anemia and ataxia telangiectasia, spontaneous and inducible chromosomal aberrations primarily of the chromatid type are increased in patients with IP. Both Fanconi anemia and ataxia telangiectasia are genetic diseases that predispose to cancer. A case report of an infant with IP and malignancy (rhabdoid tumor of the kidney) is presented, and five previously reported cases of this association are reviewed. The malignancies in all of these cases occurred before age three, whereas malignancy associated with Fanconi anemia and ataxia telangiectasia tends to appear in late childhood or in adulthood. The chromosomal instability seen with IP may increase the risk for malignancy in young children.