Then, among the genomic variations observed in DD, alterations in the copy number of genes in chromosomal regions 10q22, 16p12.1 and 17p12, associations with the HLA-DRB1*15 allele and a mutation in the rRNA 16s identified in forms with a matrilinear heredity, were reported.
HLA-DRB1*15 phenotype frequency was higher in DD positive Caucasoids (37.3%) when compared with control data (20.9%) (corrected P=0.029): we conclude that in Caucasoids of European origin, HLA-DRB1*15 is associated with risk of developing DD.