title: Familial clustering of giant congenital melanocytic nevi.
abstract: Giant congenital melanocytic nevus (GCMN) is an infrequently occurring congenital malformation. GCMN generally occurs in isolation but rare familial occurrence points to a genetic background. We present two cases of familial GCMN: one with two affected siblings and another with two affected double second cousins. Familial occurrence of GCMN reported in literature is reviewed and an overview of the embryology and proliferation given, illustrating the plethora of factors that might lead to GCMN formation. The pattern of inheritance is likely not Mendelian and discordance in identical twins and the segmental distribution of lesions suggest a post-zygotic mutation. A polygenic paradominant inheritance best explains the clinically observed transmission pattern. Candidate genes include those influencing neural crest development and melanocyte proliferation.
authors.affiliation: Department of Plastic, Reconstructive and Hand Surgery, Academic Medical Centre, University of Amsterdam, The Netherlands. rdewijn@hotmail.com
authors.forename: Robert S
authors.initials: RS
authors.lastname: de Wijn
authors.forename: Laura H
authors.initials: LH
authors.lastname: Zaal
authors.forename: Raoul C M
authors.initials: RC
authors.lastname: Hennekam
authors.forename: Chantal M A M
authors.initials: CM
authors.lastname: van der Horst
mesh_terms: D016000:Cluster Analysis; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D009508:Nevus, Pigmented / Q000151:congenital / Q000235:genetics* / Q000473:pathology*; D012878:Skin Neoplasms / Q000151:congenital / Q000235:genetics* / Q000473:pathology*