Coding regions of INHBA, SFRP4 and HOXA10 are not implicated in familial endometriosis linked to chromosome 7p13-15

Endometriosis is a common, chronic gynaecological disease affecting up to 10% of women in their reproductive years. Its aetiology still remains unclear, but evidence indicates genetic factors play a role. We previously identified a region of significant linkage on chromosome 7 in 52 families comprising at least three affected women, stretching similar to 6.4 Mb. We screened coding regions and parts of the regulatory regions of three candidate genes with a known role in endometrial development and function-INHBA, SFRP4 and HOXA10-located under or very near the linkage peak, for potential causal mutations using Sanger sequencing. Sequencing was conducted in 47 cases from the 15 families contributing most to the linkage signal (Z(mean) >= 1). Minor allele frequencies (MAFs) of observed variants were compared with MAFs from two publicly available reference populations of European ancestry: 60 individuals in HapMap and 150 individuals in the 1000 Genomes Project. A total of 11 variants were found, 5 (45%) of which were common (MAF > 0.05) among the 15 case families and the reference populations (P-values for MAF difference: 0.88-1.00). The remaining six were rare and unlikely to be individually or cumulatively responsible for the linkage signal. The results indicate that the coding regions of these three genes do not harbour mutations responsible for linkage to endometriosis in these families.