Delayed presentation of rickets in a child with labyrinthine aplasia, microtia and microdontia (LAMM) syndrome

Complete Labyrinthine Aplasia: A Unique Sign for Targeted Genetic Testing in Hearing Loss

Complete labyrinthine aplasia (CLA) is a rare inner ear anomaly. The only identified genetic cause of CLA with severe sensorineural hearing loss is labyrinthine aplasia, microtia, and microdontia (LAMM) syndrome. Here we reported a child who presented with syndromic hearing loss and was diagnosed with LAMM syndrome. Genetic evaluation provided the family with confirmation of the diagnosis, provision of the prognosis, genetic counselling, and prenatal diagnosis. This report highlighted that CLA should be recognized as a unique sign to diagnose LAMM syndrome, to analyze FGF3 gene mutation, and also demonstrated the utility of genetic testing in patients with suspected LAMM syndrome to provide exact diagnosis and further management.

Three New Mutations and Mild, Asymmetrical Phenotype in the Highly Distinctive LAMM Syndrome: A Report of Eight Further Cases

Labyrinthine aplasia, microtia, and microdontia (LAMM) is an autosomal recessive condition causing profound congenital deafness, complete absence of inner ear structures (usually Michel’s aplasia), microtia (usually type 1) and microdontia. To date, several families have been described with this condition and a number of mutations has been reported. We report on eight further cases of LAMM syndrome including three novel mutations, c. 173T>C p.L58P; c. 284G>A p.(Arg95Gln) and c.325_327delinsA p.(Glu109Thrfs*18). Congenital deafness was the primary presenting feature in all affected individuals and consanguinity in all but two families. We compare the features in our patients to those previously reported in LAMM, and describe a milder, asymmetrical phenotype associated with FGF3 mutations.