Genetic Analysis and Multimodal Retinal Imaging of Asymptomatic Fovea Plana Cases in the General Population

Summary

Albinism is a genetic condition, resulting from mutations in at least 19 known genes responsible for the production of melanin in the skin, hair and eyes.

Ophthalmological manifestations are a constant feature of this disease. Albinism is believed to be responsible for 5% of visual impairments worldwide and all albino patients have some degree of fovea plana. In the milder forms, it is a slightly less marked foveolar depression with conservation of the normal diameter of the cones and, therefore, good visual function.

In addition to its known association with various ocular pathologies such as albinism, aniridia, nanophthalmia and retinopathy of prematurity, fovea plana was found in 3% of a population of normal children (without known ocular or systemic pathology) in a study conducted in 2014 to determine a pediatric normative basis for macular volume measured by optical coherence imaging (Stratus OCT).

More recently, a study carried out at the Hospital Foundation Adolphe de Rothschild showed that at least 35% of parents of albino children, who are totally asymptomatic, present with fovea plana in OCT. This frequency is higher than the 3% prevalence of fovea plana in asymptomatic subjects without a family history of albinism, suggesting a modulation of heterozygosity for a known gene for albinism.

The aim of this study is to verify, in patients with fortuitously discovered fovea plana (preoperative OCT for cataract surgery), with conservation of visual function and without known or manifest albinism, whether they are carriers of mutation in one of the genes referenced for albinism. This will also allow us to characterize these foveolar profiles in OCT according to the classification of Thomas et al., as well as in terms of retinal capillary density in OCT-Angiography, in order to know whether it is the same type of fovea plana or if the phenotype differs depending on the genetic damage.

Conditions

• Fovea Plana
• Albinism

Interventions

GENETIC

Genetic analysis

Patient exome sequencing will be performed by Illumina technology on the NextSeq 550 sequencer. Briefly, the exons of the genes are selected by capture and are amplified by PCR simultaneously, in a single reaction, and then sequenced by Illumina technology. The analysis will only concern genes involved in albinism and in genetic pathologies associated with fovea plana.

PROCEDURE

Ophthalmologic exam

Standard ophthalmologic assessment (measurement of visual acuity, measurement of intraocular pressure, slit lamp examination), OCT-B scan, OCT-Angiography, Adaptive optics

Sponsors & Collaborators

• Fondation Ophtalmologique Adolphe de Rothschild

  lead NETWORK

Principal Investigators

• Raphaël LEJOYEUX, MD · Hôpital Fondation A. de Rothschild

Study Design

Allocation

NA

Purpose

SCREENING

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2020-12-17

Primary Completion

2023-11-02

Completion

2023-11-02

Countries

• France

Study Locations