[Linear porokeratosis of Mibelli in monozygotic twin girls].

Two monozygotic female twins with linear porokeratosis of Mibelli are described. One had only minimal lesions of the right elbow. The other had a linear lesion of the right arm following Blaschko's lines. Monozygotism was established using DNA fingerprinting. A single-gene defect of variable expressivity involving the clonal development of epidermal cutaneous cells according to the lines of cutaneous embryogenesis is suspected. Dithranol and carbon dioxide laser treatment are discussed.