OMIM ID:
Myopia and Deafness
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
High myopia (6-11D) is usually diagnosed during infancy or in the first year of life. Nine patients so far reported have ranged in age from 13 to 60 years if age. Vitreoretinal degeneration has not been reported.
Systemic Features
Prelingual hearing loss has been identified in all patients, ranging in severity from moderate to severe. No other neurological problems have been found. CT scans of the temporal bone are normal. No developmental delays or cognitive deficits have been identified.
Genetics
Inheritance
SLITRK family genes code for membrane proteins, expressed primarily in neural tissues. Mutations in SLITRK6 in the reported families cause loss of function. In cultured cells from rodents the protein product impacts synapse induction and neurite modulation. In Slitrk6 knockout mice, there is a reduction of cochlear innervations with reduced startle responses and impaired brainstem responses. Axial length in these mice is normal at birth but adults have a significant increase in eye size.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.