cone-rod dystrophy 19

Cone-rod dystrophy 19 is an inherited retinal disorder that affects both the cone and rod cells responsible for vision. It is caused by mutations in the TTLL5 gene, which plays a key role in the normal functioning of photoreceptors. Individuals with this condition typically present with reduced visual acuity and abnormal findings on electrophysiological testing, and some may also develop high myopia. Although exact prevalence figures are not available, this disorder is understood to be uncommon and its presentation can vary among affected individuals.

The clinical presentation of cone-rod dystrophy 19 is primarily marked by reduced visual acuity and an undetectable pattern electroretinogram, both of which are consistently reported in affected individuals. High myopia is observed in a subset of patients, occurring in approximately 30-79% of cases, and may contribute to further visual challenges. Not all individuals experience every symptom, and the severity as well as combination of features can vary widely between patients.

Cone-rod dystrophy 19 is caused by pathogenic variants in the TTLL5 gene. The protein encoded by TTLL5 is important for the proper functioning of photoreceptor cells in the retina, and defects in this gene disrupt normal visual processing. This condition is inherited in an autosomal recessive manner, which means that both copies of the gene must have a mutation for the disorder to manifest. Because it follows this pattern, each sibling of an affected individual has a 25% chance of being affected, and genetic counseling is recommended to help families understand the risks and implications for future pregnancies. Associated genes include TTLL5.