A novel homozygous MYO7A mutation involved in a Venezuelan population with high frequency of USHER1B

Macanao's population in Venezuela has perhaps the greatest incidence of USH1B known in Latin America (79 cases per 100,000 population); however, until now no mutation in the MYO7A gene had been reported for this population.

This study aimed to evaluate the entire coding region of the MYO7A gene by direct sequencing of PCR products obtained from patients clinically diagnosed with USH1B.

A novel mutation named c.6079_6081del was detected on exon 45 of the MYO7A gene, causing the loss of a single histidine amino acid at codon 2027 (p.H2027del) located within the second FERM domain of the human protein myosin VIIA. Three patients with clinical diagnosis of USH1B were detected positive in homozygosis for the c.6079_6081del mutation; whereas six people from the same affected family were heterozygotes and three other family members were negative.

We suggest that this new mutation named c.6079_6081del (p.H2027del) is the main cause of deaf-blindness found in this family clinically diagnosed as USH1B. Additional studies should be performed on this population to determine whether the c.6079_6081del mutation is the main cause of USH1B for the rest of the population.