Implications of population history of European Romani on genetic susceptibility to disease.

OBJECTIVES: The population history of European Romani is characterized by extensive bottleneck and admixture events, but the impact of this unique demographic history on the genetic risk for disease remains unresolved. METHODS: Genome-wide SNP data on Romani, non-Romani Europeans and Indians were analyzed. The excess of homozygous variants in Romani genomes was assessed according to their potential functional effect. We also explored the frequencies of risk variants associated with five common diseases which are present at an increased prevalence in Romani compared to other Europeans. RESULTS: Slightly deleterious variants are present at increased frequencies in European Romani, likely a result of relaxed purifying selection due to bottlenecks in their population history. The frequencies of SNPs associated with common metabolic and cardiovascular diseases are also increased compared to their European hosts. CONCLUSIONS: As observed in other founder populations, we confirm the impact of bottlenecks on the abundance of slightly deleterious variants in Romani groups, probably including metabolic and cardiovascular risk variants.