An unusual human mosaic for skin pigmentation.

Patterned pigmentary disturbances are seen in a large variety of human genetic disorders. Cytogenetic studies have provided evidence that such skin lesions often reflect chromosomal mosaicism. In addition to the well-known pattern of Blaschko's lines a classification of several distinct types was proposed by Happle. This report add the case of a boy with an unusual mosaic-like distribution of skin pigmentation and a further chromosomal anomaly which has not been described in pigmentary mosaicism previously. The proband was born after an uneventful pregnancy and delivery. Developmental milestones were delayed. A generalised hirsutism was noted with a facial dysmorphia: coarse facies. short philtrum, synophris, and large low set years. Hyperpigmentation followed a checkerboard pattern: alternating squares of pigmentary anomalies with a sharp midline separation. Cytogenetic findings Included a normal karyotype (peripheral blood) and a mosaicism 12q;14q translocation (70% of fibroblasts). The present case stresses the importance of careful chromosomal analysis of different tissues in patients with pigmentary anomalies.