Cutis tricolor parvimaculata in two patients with ring chromosome 15 syndrome.

Two unrelated girls presented with multiple disseminated, paired, small café-au-lait spots and hypopigmented macules, suggesting didymosis (twin spotting). The girls also had growth retardation, microcephaly, hypertelorism, triangular facies, and a 46,XY, r(15) karyotype. The term cutis tricolor parvimaculata has been proposed to describe a twin spot phenomenon characterized by small, paired hypochromic and hyperchromic macules on a background of normal intermediate-pigmented skin. It has been hypothesized that the underlying gene locus of this phenomenon is a hot spot for postzygotic recombination, resulting in multiple pigmentary twin spots. Future clinical research may show whether analogous "simple" twin-spot phenotypes in the form of cutis tricolor parvimaculata may be considered a further cutaneous sign of the ring chromosome 15 syndrome.