Focal dermal hypoplasia in a male patient due to mosaicism for a novel PORCN single nucleotide deletion.

BACKGROUND: Focal dermal hypoplasia (FDH) is an X-linked dominant disorder caused by nonsense mutations and deletions in the PORCN gene coding for a transmembrane endoplasmic reticulum protein required for Wingless signalling. Symptoms consist mainly of linear atrophic skin defects, skeletal deformities and, in many cases, mental retardation. Osteopathia striata is a nearly constant feature. Approximately 90% of patients are women. A few instances of father-to-daughter transmission and a number of sporadic male cases presumably as a result of somatic mosaicism have been recorded.

OBJECTIVES: The aim of this study was to demonstrate the presence of somatic mosaicism for PORCN mutations in a male patient.

METHODS: We sequenced the PORCN gene in different tissues from a boy with symptoms of FDH.

RESULTS: We demonstrate post-zygotic mosaicism for a novel deletion in the PORCN gene.

CONCLUSIONS: A novel PORCN deletion, present in a post-zygotic mosaic, causes focal dermal hyplasia in a male patient.