Autozygosity-driven genetic diagnosis in consanguineous families from Italy and the Greater Middle East

AbstractAutozygosity-driven exome analysis has been shown effective for identification of genes underlying recessive diseases especially in countries of the so-called Greater Middle East (GME), where high consanguinity unravels the phenotypic effects of recessive alleles and large family sizes facilitate homozygosity mapping. In Italy, as in most European countries, consanguinity is estimated low. Nonetheless, consanguineous Italian families are not uncommon in publications of genetic findings and are often key to new associations of genes with rare diseases. We collected 52 patients from 47 consanguineous families with suspected recessive diseases, 29 originated in GME countries and 18 of Italian descent. We performed autozygosity-driven exome analysis by detecting long runs of homozygosity (ROHs  >  1.5 Mb) and by prioritizingcandidate clinical variants within. We identified a pathogenic synonymous variant that had been previously missed inNARS2 and we increased an initial high diagnostic rate (47%) to 55% by matchmaking our candidate genes and including in the analysis shorter ROHs that may also happen to be autozygous. GME and Italian families contributed to diagnostic yield comparably. We found no significant difference either in the extension of the autozygous genome, or in the distribution ofcandidate clinical variants between GME and Italian families, while we showed that the average autozygous genome was larger and the mean number ofcandidate clinical variant...
Source: Human Genetics - Category: Genetics & Stem Cells Source Type: research