Catalogue of inherited autosomal recessive disorders found amongst the Roma population of Europe.

Background: The Roma population are an endogamous, genetically isolated, minority population who migrated from North-Western India to Europe from the 10 Century throughout the Byzantine period and continues to the present day. Approximately 10-12 million Romani people reside in segregated settlements in Europe, and smaller populations live in North America and China. In addition to the endogamy, they also practice consanguinity. This has resulted in a higher frequency of rare autosomal recessive disorders some of which are unique to the Roma population. Some disorders result from founder variants whilst others are private variants, occurring within one nuclear family. Most are found as homozygous variants but compound heterozygosity is seen in a number of conditions.

Objective(s): Clinicians and scientists with experience in managing and diagnosing rare diseases in this population in Ireland, Romania and Greece have developed a comprehensive catalogue of autosomal recessive inherited disorders found in the Roma population. Our aim is that this catalogue will aid rapid diagnosis and highlight the differential diagnoses to consider in challenging cases.

Methods: We performed a detailed literature search to identify relevant publications and disease variants described in patients whose ethnicity was described as Roma. In addition, we interrogated data from local clinicians and colleagues in Ireland and Romania to collect additional unpublished variants which have yet to be reported in the medical literature. Where possible, we have mapped these disorders back to their European country of origin. Furthermore, we searched the variants allele frequencies on ClinVar. We analysed exome data from New Delhi, India to trace any of these founder variants back their origins.

Results: We identified 90 distinct autosomal recessive disorders, manifesting as 91 distinct phenotypes and 111 pathogenic disease variants. These include both published (n=91) and unpublished (n=20) findings identified in the Roma population in Europe. The Indian exome data revealed that only 12/111 variants were identified.

Conclusion: We have assembled a catalogue of inherited autosomal recessive disorders and 111 pathogenic variants found in the Roma population. We hope that this will assist the medical and scientific community to make prompt diagnoses and consider adaptation of a targeted genetic approach to facilitate timely and cost-effective diagnoses in this population.