Large-scale genetic analyses in an understudied disease: haemorrhoidal disease

Approximately 20% of the US population have ever been diagnosed with haemorrhoidal disease, and out of those individuals, one in five reports to have had surgery for his or her haemorrhoids. Outpatient and emergency department visits to gastroenterologists and surgeons for haemorrhoids outnumber those for colon cancer, inflammatory bowel disease or irritable bowel syndrome. Historically accepted notions that constipation and a low-fibre diet contribute to disease development have not been confirmed in large US and UK survey and registry data studies.1 Moreover, these studies found that generally accepted symptoms of haemorrhoids, like pruritus, pain, mucus discharge and bleeding, occur just as frequently in individuals without haemorrhoids. Haemorrhoidal disease is a classic example of a disease that has a large burden within the population, but for which scientific knowledge and research efforts are nonetheless very limited. A recent narrative review by Sandler and Peery thoroughly exposed the large gaps in our understanding of the underlying disease mechanisms and the lack of evidence-based treatment options in haemorrhoidal disease.2 In Gut , Zheng et al focused on the mechanisms underlying haemorrhoidal disease and set out to study the genetic components in its development.3 The study is noteworthy and laudable for two reasons. First of all, it represents a state-of-the-art genome-wide association study (GWAS) making use of available data from (population based) biobanks resulting in a massive study involving just under a million participants. …