International effort identified new and different causative gene variants for a group of diseases that can lead to severe vision loss or blindness
October 19, 2021

An international team of researchers, led by scientists at University of California San Diego and Shiley Eye Institute at UC San Diego Health, has broadened and deepened understanding of how inherited retinal dystrophies (IRDs) affect different populations of people and, in the process, have identified new gene variants that may cause the diseases.

The researchers conducted whole-genome sequences (WGS) of 409 persons from 108 unrelated family lineages, each with a previously diagnosed IRD. WGS is a process of determining the entirety, or near-entirety, of the DNA sequence of an individual. It provides a comprehensive portrait of the person’s entire genome, including mutations and variants, which can be used for broad comparative purposes. 

Study participants were recruited from three different geographic regions: Mexico, Pakistan and European Americans living in the United States. Genomic analyses were conducted from blood samples taken from all participants, which revealed causative variants in 62 of the 108 lineages. A total of 94 gene variants were found in the 62 families: 52 variants had previously been identified as causative and 42 had not. Surprisingly, more than half of the new variants were not listed in the Genome Aggregation Database, an international compilation of genomic data.