Enamel-renal Syndrome In 2 Patients With A Mutation In Fam20 A And Atypical Hypertrichosis And Hearing Loss Phenotypes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Enamel-renal syndrome (OMIM #204690) is an uncommon disorder characterized by amelogenesis imperfecta and nephrocalcinosis and is caused by mutations in FAM20 A. We report 2 patients with enamel-renal syndrome who exhibited the typical features of this syndrome and a homozygous nonsense mutation in the FAM20 A gene (c.406 C>T), genetically confirming the diagnosis. They also exhibited 2 undescribed clinical features, hypertrichosis and hearing loss. Alterations in genes frequently associated with nonsyndromic hearing loss in the Brazilian population, including connexin 26 (GJB2), connexin 30 (GJB6) and mitochondrial 12 S rRNA (m.A1555 G mutation), were not found. These results suggest a putative function of FAM20 A in the development of the inner ear and in the formation of hair. The presence of nephrocalcinosis is a risk factor for renal impairment, and it is important to perform regular renal monitoring in order to avoid renal failure.1232229+Fundacao de Amparo a Pesquisa do Estado de Minas Gerais, Belo Horizonte, BrazilConselho Nacional de Desenvolvimento Cientifico e Tecnologico, BrazilConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq