Abstract
Purpose :
Inherited retinal dystrophies (IRDs) are a group of disorders characterized by genetic and phenotypic heterogeneity affecting photoreceptor function. The purpose of this study was to characterize the clinical spectrum and to examine the prevalence of IRDs in a subset within the South Indian population
Methods :
Patients seen in the retinal dystrophy clinic at Aravind Eye Hospital in Pondicherry from 2016 to 2019 underwent detailed ophthalmic examination including corrected visual acuity, slit-lamp examination, color fundus imaging, fundus autofluorescence, optical coherence tomography and electroretinography (ERG). Family history and inheritance patterns were documented and pedigrees were drawn.
Results :
Over the 3-year period, 601 patients were clinically characterized as being affected by IRDs. Of the 601 cases 41% were female and 59% were male, and 52 (8%) were ≤ 10 yrs. (years) old. In a majority of patients (n=279, 46% age 4-82 yrs.) characteristic features of retinitis pigments (RP) were present including reduced ERG rod function and fundus changes. Of the 279 RP cases 100 cases (36%, age 8-75 yrs.) had advanced disease. Cone- or cone-rod dysfunction, classified using the ERG accounted for 12% of the cases, (n=69, age 8-69 yrs. Typical features of Stargardts were clinically evident in 13% cases (n=77, age range 6-75 yrs.). Other forms of macular dystrophies including Best disease represented 8% (n=50). Among syndromic RP cases, Usher syndrome was 4% (n=22, age 8-45 yrs.) and Bardet-Biedl was 0.83% (n=5, age 7-19 yrs.). Cases with ≤ 1% representation included choroideremia, Gyrate atrophy, congenital stationary night blindness, X-linked retinoschisis, Oguchi disease and Bietti Crystalline dystrophy. Additionally, 15 cases (2.5%) were in the unclassified category. Consanguinity was present in almost half the cases at 48% (n=288).
Conclusions :
Retinitis pigmentosa accounted for almost half of the IRD cases. The high prevalence of consanguinity in this part of the country warrants an increased public awareness for the risk of IRDs to patients and to their family members. Disease prevalence, the diagnostic spectrum, and the rapid progress in clinical trials for therapeutic interventions in IRDs, emphasize the need for genetic testing. A genetic diagnosis will be essential for future treatment options in these patients.
This is a 2020 ARVO Annual Meeting abstract.