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

ABSTRACT

Background: 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.

Materials and Methods: 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.

Results: 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.

Conclusion: 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.

KEYWORDS:

• c.6079_6081del mutation
• FERM domains
• MYO7A
• myosin VIIA protein
• USHER1B

Acknowledgments

We are most grateful to the families for their willingness to participate in this study. We also thank Dr. José Millan from the Unidad de Genética, Hospital Universitario La Fe, Valencia, España for providing us with the oligonucleotides and Dr. Judith Recht for helpful discussions.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

The study was performed with financial support from Fondo Nacional de Ciencia, Tecnología e Innovación (FONACIT) del Ministerio de Ciencia y Tecnología de Venezuela (S1-99000112) and Decanato de Investigación y Desarrollo (DID) de la Universidad Simón Bolívar, Caracas/Venezuela.

Additional information

Funding

The study was performed with financial support from Fondo Nacional de Ciencia, Tecnología e Innovación (FONACIT) del Ministerio de Ciencia y Tecnología de Venezuela (S1-99000112) and Decanato de Investigación y Desarrollo (DID) de la Universidad Simón Bolívar, Caracas/Venezuela.