HLA polymorphism in a Majorcan population of Jewish descent: comparison with Majorca, Minorca, Ibiza (Balearic Islands) and other Jewish communities.

'Chueta' was the name given to the Catholic descendants of Jewish victims of the last Spanish Inquisition process in Majorca Island in the western Mediterranean. We have studied the allele distribution of HLA-A, -B, -Cw, -DRB1 and -DQB1 loci of 103 random, healthy, unrelated individuals belonging to the ancient Majorcan Jewish community, known locally as Chuetas, and 589 individuals from the Balearic population selected because of their typical Balearic - Majorca, Minorca or Ibiza - lineages and according to their ancestor's place of birth. Our aim was to establish the genetic relationship between Majorcan Chuetas, and Balearic and other Jewish and Mediterranean populations. Our results have shown that, to a remarkable extent, they have retained their biological identity, with a unique pattern, in terms of gene and haplotype frequencies, separate from the other populations of Majorca. The Chuetas were found to be more related to Moroccan and Libyan Jews than other Majorcans. Characteristic Jewish haplotypes, A26-B38-DRB1*13, A24-B38-DRB1*11, A1-B52-DRB1*15/16, were found in our study. Some peculiarities were observed in the distribution of common haplotypes among the three main Balearic Islands. The Ibizan population was genetically different from the other Balearic populations, with a high frequency of some haplotypes, for example, A29-Cw*16-B44-DRB1*07-DQB1*03; A1-Cw*07-B8-DRB1*03-DQB1*02. We also found a new haplotype, A25-Cw*12-B39-DRB1*11-DQB1*03(3.5%), in Ibizans and a more limited variability in the HLA alleles that were expressed, perhaps because of genetic isolation. The genetic diversity of the populations from Majorca and Minorca were similar and more related to the mainland Spanish population.