Delineation of a newly recognized neurocutaneous malformation syndrome with "cutis tricolor".

The term "cutis tricolor" describes the combination of congenital hyper- and hypo-pigmented lesions, in close proximity to each other with a background of normal skin. Cutis tricolor represents twin spotting and has been reported as an isolated skin disorder or as part of a neurocutaneous malformation syndrome. We report on an 11-year-old girl with diffuse pigmentary changes of the cutis tricolor type, facial anomalies, mental retardation, epileptic seizures, EEG anomalies, small skull, progressive double-curved thoracolumbar/lumbar scoliosis with vertebral scalloping and dysplastic vertebral pedicles and ribs, and tibial bowing. These abnormalities are similar to those observed in cases reported by Happle et al. [1997: J Med Genet 34:676-678] and Ruggieri [2000: Eur J Pediatr 159:745-749]. Additionally, our patient had altered behavior and hypoplasia of the corpus callosum. This constellation of abnormalities represents a newly recognized neurocutaneous malformation syndrome. The phenotype could be explained by somatic mutation. Loss of heterozygosity at an early developmental stage would give rise to one single mosaic skin disorder (e.g., generalized skin manifestations of the cutis tricolor type in association to extracutaneous anomalies). Postzygotic recombination occurring later during embryogenesis would give rise to solitary lesions confined to the skin.