Twin study shows hidradenitis suppurativa etiology may be genetic

A study involving more than 4,000 twins showed that hidradenitis suppurativa disease pathogenesis may be more genetically driven than previously thought.

“Hidradenitis suppurativa is a chronic, inflammatory skin disease in which genetic factors are considered to play a role, with up to 38% of patients reporting a family history,” Kelsey R. van Straalen, MD, of the department of dermatology at Erasmus MC, University Medical Center Rotterdam, Netherlands, and the European Reference Network-Skin, Paris, and colleagues wrote. “Variations in the gamma-secretase genes are found mainly in familial cases with an autosomal dominant pattern of inheritance.”

Previous data have shown that these genetic variations are uncommon among patients with HS, even in those with a family history of the disease.

Using data from the Netherlands Twin Register, van Straalen and colleagues conducted a cross-sectional study to determine whether HS is heritable.

Eligible participants had self-reported HS between 2011 and 2016. The data set included findings for 978 female monozygotic twin pairs, 344 male monozygotic twin pairs, 426 female dizygotic twin pairs, 167 male dizygotic twin pairs and 428 dizygotic twin pairs of the opposite sex, the study said.

The ratio of susceptibility to HS resulting from additive genetic factors, which the researchers described as narrow-sense heritability, served as the primary outcome measure, along with dominant genetic factors, common or shared environmental factors, or unshared or unique environmental factors.

Results showed that HS occurred in 1.2% of 4,686 twins. The researchers also observed a 77% (95% CI, 54%-90%) narrow-sense heritability rate of the disease. Unshared or unique environmental factors comprised the remainder of the causes. This finding is based on a model that adjusted for age and additive genetic and environmental factors.

Disease occurred at a mean age of 32.7 years.

“The high heritability found in this study suggests a stronger than previously assumed genetic basis of hidradenitis suppurativa,” the researchers wrote. That said, they acknowledged the presence of concomitant environmental factors that also contribute to disease pathogenesis and support a multifactorial etiology. “The results of this study strongly support the need for a global genome-wide association study in the general population of patients with hidradenitis suppurativa.”