Mild retinitis pigmentosa, including sector retinitis pigmentosa associated with 2 pathogenic variants in CDH23.

BACKGROUND: Biallelic pathogenic variants in CDH23 can cause Usher syndrome type I (USH1), typically characterized by sensorineural hearing loss, variable vestibular areflexia, and a progressive form of rod-cone dystrophy. While missense variants in CDH23 can cause DFNB12 deafness, other variants can affect the cadherin 23 function, more severely causing Usher syndrome type I D. The main purpose of our study is to describe the genotypes and phenotypes of patients with mild retinitis pigmentosa (RP), including sector RP with two pathogenic variants in CDH23. MATERIALS AND METHODS: Clinical examination included medical history, comprehensive ophthalmologic examination, and multimodal retinal imaging, and in case 1 and 2, full-field electroretinography (ERG). Genetic analysis was performed in all cases, and segregation testing of proband relatives was performed in case 1 and 3. RESULTS: Three unrelated cases presented with variable clinical phenotype for USH1 and were found to have two pathogenic variants in CDH23, with missense variant, c.5237 G > A: p.Arg1746Gln being common to all. All probands had mild to profound hearing loss. Case 1 and 3 had mild RP with mid peripheral and posterior pole sparing, while case 2 had sector RP. ERG results were consistent with the marked loss of retinal function in both eyes at the level of photoreceptor in case 1 and case 2, with normal peak time in the former. CONCLUSION: Patients harbouring c.5237 G > A: p.Arg1746Gln variants in CDH23 can present with a mild phenotype including sector RP. This can aid in better genetic counselling and in prognostication.

Closure rate and recovery of subfoveal microstructures following conventional internal limiting membrane peeling versus per fluoro octane-assisted inverted flap for large macular holes - A randomized controlled trial (InFlap Study).

PURPOSE: To analyze the outcomes following conventional internal limiting membrane (ILM) peeling versus perfluoro octane-assisted inverted flap technique for large macular holes (MH). METHODS: A consecutive 99 eyes of 99 patients were enrolled {45 - conventional group and 54 - inverted flap (InFlap) group}. The primary outcome was a difference in closure rate. Secondary outcomes were differences in best-corrected visual acuity (BCVA), restoration of external limiting membrane (ELM) and ellipsoid zone (EZ) between groups at 3 (primary endpoint), 6 and 12 (secondary endpoints) months. Additionally, the effect of different gas tamponades on closure rates, ILM flap disintegration in InFlap group, and subfoveal thickness (SFT) between groups in closed. RESULTS: At 3 months, there was no difference in the closure rate and BCVA between groups. At six months, closure rate was significantly better in the InFlap group. However, this difference was not maintained at 12 months. There was no difference in BCVA between groups at any visit. The ELM recovery was significantly higher in the conventional group at three months; however, there was no difference in ELM/EZ recovery between groups at other visits. The closure rate in the InFlap group was the same irrespective of gas tamponade. The ILM flap was identifiable in one-third of patients at 12 months. In closed MH, SFT was significantly more in InFlap group. CONCLUSION: The closure rate and visual outcomes remained similar in both groups in the immediate and long term. Conventional ILM peeling technique seems to have early ELM recovery when compared to inverted flap technique.