A very recent study published in the scientific journal PNAS highlights an estimate, on a global scale, of the frequency of individuals carrying pathogenic mutations responsible for inherited retinal dystrophies (IRD) and illustrates the prevalence of this group of diseases. These data are highly relevant for genetic diagnosis, genetic counselling and the design of new therapies.
The authors studied the information gathered in the genomic databases corresponding to 138,000 individuals and focused the study on 187 genes responsible for recessive forms of retinal dystrophies (arIRD): that is, only those who inherit two mutated alleles, one from each parent, will develop the disease.
Using genomic information from the gnomAD, Human Gene Mutation Database (HGMD) and ClinVar databases, the researchers constructed a database containing 276,921 genetic variants in the 187 IRD genes studied. Next, they applied a series of bioinformatics filtering steps to categorize them and then characterized 10,044 pathogenic mutations.
Subsequently, the researchers calculated the proportion of carriers for the set of identified mutations in six global subpopulations, reaching the conclusion that 36% of the world population (1 in 2.8 people) is a carrier, non-affected, of at least a causative mutation of arIRD. Overall, it amounts to 2.7 billion people world-wide.
Furthermore, according to the calculations made by the researchers, the proportion of affected individuals is 1 in 1,378 (5.5 million are arIRD affected people) and this frequency varies at the population level, ranging from 0.05% in the Latino population to 0.1% in East Asians.
This type of study applied to other hereditary diseases will be of great value because it will enrich personalized medicine and open new scenarios to devise new therapies.