BACKGROUND: Hidradenitis suppurativa (HS) is not a well-studied or easily treated disease. Genetic information is essential for advances in the understanding and treatment of HS. This study aims to examine mutations in the gamma-secretase complex, the Notch signalling pathway and to perform a Mendelian analysis of genetic variants that segregated with disease in a full exome sequencing of 11 families with HS.

METHOD: Whole-exome sequencing and Mendelian analysis of 11 families with HS from Denmark. Patients with a clinical diagnosis of active HS and a positive family history of HS were recruited. Consenting family members were enrolled and examined for HS as well. We included 11 families, with a total of 51 participants, 24 with HS and 27 without. Whole-exome sequencing using HiSeq platform as paired-end 2 × 150 bases was used.

RESULTS: We found mutations in the Notch pathway for all families. We found mutations in the PSENEN and APH1B of the gamma-secretase genes. We also report 161 variants of unknown significance that segregated with the disease within these families.

CONCLUSIONS: We did not find causative mutation for each family in this study, supporting the theory that HS is rarely caused by single-gene mutations. We suggest that future genetic studies should be focused on genome-wide association with thousands of cases, as this technique is better suited for suspected polygenic diseases.