Four novel C20orf54 mutations identified in Brown-Vialetto-Van Laere syndrome patients.

Brown-Vialetto-Van Laere syndrome (BVVLS) is a very rare neurodegenerative disorder characterized by pontobulbar palsy and sensorineural hearing loss. Its mode of inheritance in affected families has usually been autosomal recessive, although autosomal dominant inheritance and incomplete penetrance have also been reported. Recently, C20orf54 was identified as a causative gene for BVVLS. Twelve different mutations have so far been identified in 10 patients affected with BVVLS or the related disorder Fazio Londe syndrome. Here, results of screening of C20orf54 in three unrelated BVVLS patients are reported. Four novel mutations that affect amino acid changes, p.Asn21Ser, p.Pro220His, p.Ala312Val and p.Gly375Asp, were identified in the patients. The causative nucleotide variations were not observed in 200 control individuals. One of the patients harbored compound heterozygous mutations, but only one mutated allele was observed in each of the two remaining patients.