A novel mutation in the PORCN gene underlying a case of almost unilateral focal dermal hypoplasia.

BACKGROUND Focal dermal hypoplasia (also known as Goltz syndrome) is an X-linked dominant syndrome characterized by patchy hypoplastic skin with soft-tissue, skeletal, dental, and ocular defects that are secondary to mutations in the PORCN gene. To our knowledge, only 5 cases of focal dermal hypoplasia with unilateral presentation have been reported, and molecular studies were not performed in any of the cases. OBSERVATIONS A 17-year-old girl was seen with features of almost unilateral focal dermal hypoplasia. These included left cleft hand, dental dysplasia, left mammary hypoplasia, deviation of the sacral line, raspberrylike papillomas in the perianal region, syndactyly of the second and third digits of the left foot, and linear streaks of dermal hypoplasia and pigmented lesions on her left hemibody. CONCLUSIONS Mutation analysis of PORCN revealed a novel heterozygous mutation in exon 10, c.854-855insACCTGAC; [p.T285fsX316], resulting in a premature stop signal. Analysis of the X-chromosome inactivation status was performed on blood and skin DNA samples, showing random inactivation in blood and unaffected skin and skewed inactivation in affected skin, highlighting the role of X-chromosome inactivation in X-linked disease expression.