A Novel Mutation Involving the Initiation Codon of FGF3 in a Family Described with Complete Inner Ear Agenesis, Microtia and Major Microdontia (LAMM Syndrome)

LAMM syndrome (OMIM #610706) is a rare autosomal recessive syndrome characterized by the association of Michel aplasia, microdontiaand malformation of the external ear. Different mutations in FGF3 gene were reported in several families presenting with this syndrome. Clinical features and genetic results observed in a family with LAMM syndrome are reported. The diagnosis of isolated Michel aplasiawas initially made in this family composed of two affected children. Microtiaand microdontiawas recently evidenced in both patients suggesting the diagnosis of LAMM syndrome. New auditory and orodental iconographywas performed permitting to describe the patients’ phenotype in depth and to report rare findings of LAMM syndrome. The sequencing of FGF3 gene identified a novel missense mutation(c.2T>G), substituting the first initiator methionine in arginine, in the fibroblast growth factor3 (FGF3) at the homozygous state in both patients. LAMM syndrome was confirmed and appropriate genetic counselingperformed.