Variable expressivity of the autosomal dominant vitreoretinochoroidopathy (ADVIRC) phenotype associated with a novel variant in BEST1.

BACKGROUND: This case report explores the relationship between genetics and phenotypic variability in autosomal dominant vitreoretinochoroidopathy (ADVIRC). The study focuses on a case presenting a novel mutation in the BEST1 gene and its phenotype in the case's relatives, shedding light on the structural and functional intricacies underlying this rare ophthalmologic disorder. CASE PRESENTATION: A 33-year-old female presented for consultation with a history of bilateral retinal damage accompanied by a complaint of decreased visual acuity, progressive visual field deficit, and night blindness over the past year. Ophthalmic examination revealed a distinctive phenotype, including fibrillar vitreous, pigmented cells, and atrophic hyperpigmented retina in the periphery which was suggestive of a diagnosis of ADVIRC. Genetic testing revealed a heterozygous c.1101-1 G>T variant in BEST1, a novel splice site mutation. Functional analysis confirmed its impact on pre-mRNA splicing, resulting in an in-frame deletion (p(Ser367_Asn579del)). Family investigation revealed varying degrees of ophthalmologic impairment in the patient's mother and half-sister, both carrying the same mutation. CONCLUSIONS: This case report provides the first clinical description of the c.1101-1 G>T mutation in the BEST1 gene associated with ADVIRC. The presence of intrafamilial variability, as evidenced by the differing clinical features observed in the index case and her half-sister, suggests the potential involvement of mechanisms influencing phenotype expression.Abbreviation: ADVIRC : autosomal dominant vitreoretinochoroidopathy; RNA : ribonucleic acid; RPE : retinal pigment epithelium.

Pros and cons of internal limiting membrane peeling during epiretinal membrane surgery: a randomised clinical trial with microperimetry (PEELING).

BACKGROUND: After idiopathic epiretinal membrane (iERM) removal, it is unclear whether the internal limiting membrane (ILM) should be removed. The objective was to assess if active ILM peeling after iERM removal could induce microscotomas. METHODS: The PEELING study is a national randomised clinical trial. When no spontaneous ILM peeling occurred, patients were randomised either to the ILM peeling or no ILM peeling group. Groups were compared at the month 1 (M1), M6 and M12 visits in terms of microperimetry, best-corrected visual acuity (BCVA) and optical coherence tomography findings. The primary outcome was the difference in microscotoma number between baseline and M6. RESULTS: 213 patients were included, 101 experienced spontaneous ILM peeling and 100 were randomised to the ILM peeling (n=51) or no ILM peeling group (n=49). The difference in microscotoma number between both groups was significant at M1 (3.9 more microscotomas in ILM peeling group, (0.8;7.0) p=0.0155) but not at M6 (2.1 more microscotomas in ILM peeling group (-0.5;4.7) p=0.1155). Only in the no ILM peeling group, the number of microscotomas significantly decreased and the mean retinal sensitivity significantly improved. The ERM recurred in nine patients in the no ILM peeling group (19.6%) versus zero in the ILM peeling group (p=0.0008): two of them underwent revision surgery. There was no difference in mean BCVA and microperimetry between patients experiencing or not a recurrence at M12. CONCLUSION: Spontaneous ILM peeling is very common. Active ILM peeling prevents anatomical ERM recurrence but may induce retinal impairments and delay visual recovery. TRIAL REGISTRATION: NCT02146144.

Does internal limiting membrane peeling during epiretinal membrane surgery induce microscotomas on microperimetry? Study protocol for PEELING, a randomized controlled clinical trial.

BACKGROUND: The epiretinal membrane (ERM) is a degenerative condition associated with age, which can cause loss of vision and/or metamorphopsia. The treatment of symptomatic ERM involves surgical removal including a vitrectomy followed by peeling of the ERM using a microforceps. As the internal limiting membrane (ILM) is adherent to the ERM, it is sometimes removed with it (spontaneous peeling). If ILM remains in place, it can be removed to reduce ERM recurrence. However, it is important to clarify the safety of ILM peeling, while it increases surgical risks and cause histological disorganization of the retina that can lead to microscotomas, may be responsible for definitive visual discomfort. METHODS: PEELING is a prospective, randomized, controlled, single-blind, and multicentered trial with two parallel arms. This study investigates the benefit/risk ratio of active ILM peeling among individuals undergoing ERM surgery without spontaneous ILM peeling. Randomization is done in the operating room after ERM removal if ILM remains in place. After randomization, the two groups-"active peeling of the ILM" and "no peeling of the ILM"-are compared during a total of three follow-up visits scheduled at month 1, month 6, and month 12. Primary endpoint is the difference in microscotomas before surgery and 6 months after surgery. Patients with spontaneous peeling are not randomized and are included in the ancillary study with the same follow-up visits and the same examinations as the principal study. Relevant inclusion criteria involve individuals aged > 18 years living with idiopathic symptomatic ERM, including pseudophakic patients with transparent posterior capsule or open capsule or lensed patients with age-related cataracts. The calculated sample size corresponds to 53 randomized eyes (one eye/patient) per arm that means 106 randomized eyes (106 randomized patients) in total and a maximum of 222 included patients (116 spontaneous peeling). DISCUSSION: ILM peeling is often practiced in ERM surgery to reduce ERM recurrence. It does not impair postoperative visual acuity, but it increases the surgical risks and causes anatomical damages. If active ILM peeling is significantly associated with more microscotomas, it may contraindicate the ILM peeling during primitive idiopathic ERM surgery. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02146144. Registered on 22 May 2014. Recruitment is still ongoing.

Safety and Long-Term Efficacy of AAV4 Gene Therapy in Patients with RPE65 Leber Congenital Amaurosis.

The aim of this study was the evaluation of the safety and efficacy of unilateral subretinal injection of the adeno-associated vector (AAV) serotypes 2 and 4 (AAV2/4) RPE65-RPE65 vector in patients with Leber congenital amaurosis (LCA) associated with RPE65 gene deficiency. We evaluated ocular and general tolerance and visual function up to 1 year after vector administration in the most severely affected eye in nine patients with retinal degeneration associated with mutations in the RPE65 gene. Patients received either low (1.22 × 1010 to 2 × 1010 vector genomes [vg]) or high (between 3.27 × 1010 and 4.8 × 1010 vg) vector doses. An ancillary study, in which six of the original nine patients participated, extended the follow-up period to 2-3.5 years. All patients showed good ophthalmological and general tolerance to the rAAV2/4-RPE65-RPE65 vector. We observed a trend toward improved visual acuity in patients with nystagmus, stabilization and improvement of the visual field, and cortical activation along visual pathways during fMRI analysis. OCT analysis after vector administration revealed no retinal thinning, except in cases of macular detachment. Our findings show that the rAAV2/4.RPE65.RPE65 vector was well tolerated in nine patients with RPE65-associated LCA. Efficacy parameters varied between patients during follow-up.