Genetic testing for hearing loss in the United States should include deletion/duplication analysis for the deafness/infertility locus at 15q15.3.

BACKGROUND

Hearing loss is the most common birth defect and the most prevalent sensorineural disorder in developed countries. More than 50% of prelingual deafness is genetic, most often autosomal recessive and nonsyndromic, of which 50% can be attributed to the disorder DFNB1, caused by mutations in GJB2 and GJB6. Sensorineural hearing loss and male infertility (Deafness-Infertility Syndrome; DIS) is a contiguous gene deletion syndrome resulting from homozygous deletion of the CATSPER2 and STRC genes on chromosome 15q15.3. Females with DIS have only hearing loss and are fertile. Until recently this syndrome has only been described in three consanguineous families and 2 nonconsanguineous families.

RESULTS

We recently indentified a patient with hearing loss and macrocephaly who was found to be homozygous for this deletion. Her nonconsanguineous parents are both carriers. We examined our database of patients tested by array CGH and determined that just over 1% of our patients are heterozygous for this deletion. If this number is representative of the general population, this implies a 1% carrier frequency and prevalence of DIS of 1 in 40,000 individuals.

CONCLUSION

We propose that DIS is a greatly under-diagnosed cause of deafness and should be considered in children with hearing loss. Likewise, current molecular genetic testing panels for hearing loss in the United States should be expanded to include deletion/duplication analysis of this region.