Deafness and Myopia Syndrome

Excerpt

Clinical characteristics: Deafness and myopia (DFNMYP) syndrome is characterized by bilateral, congenital or prelingual deafness (sensorineural hearing loss or auditory neuropathy spectrum disorder) and high myopia (>-6 diopters). In individuals with a molecularly confirmed diagnosis reported to date, hearing loss was progressive and severity ranged from moderate to profound. Vestibular testing was normal. Myopia was diagnosed at infancy or early childhood.

Diagnosis/testing: The diagnosis is established in a proband by identification of biallelic pathogenic variants in SLITRK6 on molecular genetic testing.

Management: Treatment of manifestations: For hearing loss: use of hearing habilitation devices including hearing aids and vibrotactile hearing tools; cochlear implantation may be considered in individuals with severe-to-profound sensorineural hearing loss and auditory neuropathy spectrum disorder; enrollment in appropriate early-intervention and educational programs for the hearing impaired. For myopia: routine correction of refractive error.

Surveillance: ENT and audiology evaluations at least yearly; regular speech and language evaluation to monitor language development; regular ophthalmology evaluations to monitor for potential complications from high myopia; yearly evaluations by a clinical geneticist familiar with hereditary forms of deafness.

Agents/circumstances to avoid: Known environmental factors for hearing loss (e.g., loud noises) and ototoxic medications.

Evaluation of relatives at risk: If the SLITRK6 pathogenic variants in the family are known, molecular genetic testing can be used to clarify the genetic status of at-risk sibs. If a molecular diagnosis has not been established, clinical audiology and ophthalmology evaluations should be considered for at-risk sibs.

Genetic counseling: DFNMYP syndrome is inherited in an autosomal recessive manner. At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Carrier testing for at-risk relatives and prenatal testing for a pregnancy at increased risk are possible if the SLITRK6 pathogenic variants have been identified in an affected family member.