Genome-wide analysis of 944 133 individuals provides insights into the etiology of haemorrhoidal disease

OBJECTIVE

Haemorrhoidal disease (HEM) affects a large and silently suffering fraction of the population but its aetiology, including suspected genetic predisposition, is poorly understood. We report the first genome-wide association study (GWAS) meta-analysis to identify genetic risk factors for HEM to date.

DESIGN

We conducted a GWAS meta-analysis of 218 920 patients with HEM and 725 213 controls of European ancestry. Using GWAS summary statistics, we performed multiple genetic correlation analyses between HEM and other traits as well as calculated HEM polygenic risk scores (PRS) and evaluated their translational potential in independent datasets. Using functional annotation of GWAS results, we identified HEM candidate genes, which differential expression and coexpression in HEM tissues were evaluated employing RNA-seq analyses. The localisation of expressed proteins at selected loci was investigated by immunohistochemistry.

RESULTS

We demonstrate modest heritability and genetic correlation of HEM with several other diseases from the GI, neuroaffective and cardiovascular domains. HEM PRS validated in 180 435 individuals from independent datasets allowed the identification of those at risk and correlated with younger age of onset and recurrent surgery. We identified 102 independent HEM risk loci harbouring genes whose expression is enriched in blood vessels and GI tissues, and in pathways associated with smooth muscles, epithelial and endothelial development and morphogenesis. Network transcriptomic analyses highlighted HEM gene coexpression modules that are relevant to the development and integrity of the musculoskeletal and epidermal systems, and the organisation of the extracellular matrix.

CONCLUSION

HEM has a genetic component that predisposes to smooth muscle, epithelial and connective tissue dysfunction.

Perianal streptococcal dermatitis in adults: its association with pruritic anorectal diseases is mainly caused by group B Streptococci

AIM

Although perianal streptococcal dermatitis (PSD) is well known in children, it has only rarely been documented in adults. The incidence and necessity for treatment may be underestimated. We have retrospectively identified adult patients with perianal streptococcal dermatitis.

METHOD

Patients with streptococcal anal dermatitis were identified from a prospective office database. Treatment was with oral antibiotics according to the organism sensitivity. Additional concomitant anorectal disease was treated according to standard guidelines. Patients were compared with a control group, without eczema or erythema, for the presence of β-haemolysing Streptococci on perianal swab. Demographic and microbiological data were assessed and compared between and within treatment and control groups.

RESULTS

Fifty-three (22 female) patients older than 20 (mean = 49) years of age were diagnosed with perianal streptococcal dermatitis between 2005 and 2009. In most cases group B β-haemolytic Streptococci were found. Fifty patients received antibiotics for 14 days. In 28 of 33 patients who had a post-treatment swab, the result was negative. Five patients showed Streptococci of different groups in the post-treatment swab. Of the 50 patients, 21 (42%) had no further anorectal complaint and 29 (58%) required continuing treatment for another anorectal condition. In the control group β-haemolysing Streptococcus was found in 34%. Men over 60 years of age more often required no further anorectal treatment compared with women (P < 0.05).

CONCLUSION

Perianal streptococcal dermatitis occurs in adult patients more often than reported. It is mainly caused by group B β-haemolysing Streptococcus. Its diagnosis is important because it can cause serious systemic infections, especially in the elderly and in newborns. Antibiotics resolve the condition in a high proportion of patients.

[Proctological diseases in routine urologic practice]

Nearly two third of adults will suffer from proctologic complaints. The same symptoms could also indicate or mask an anorectal carcinoma. Therefore, the first priority should be to exclude the possibility of a neoplasm of the colon, rectum and the anal canal. Knowledge of the specific anatomy of the anal canal and the patient's history will lead to an exact proctologic diagnosis: perianal thrombosis, acute thrombosed prolapsed haemorrhoidal plexus, an anal fissure, abscess and fistula are located within the highly sensitive anoderma and are characterized by pain. Perianal thrombosis, chronic fissure, abscess and fistula require surgery. Conservative treatment is the choice for an acute anal fissure, haemorrhoids grade I-II. Haemorrhoids II-III require surgery, e.g. by haemorrhoidal artery ligation, open or closed resection of the haemorrhoidal plexus, reconstruction of the anal canal or stapled mucosectomy. Perianal diseases such as perianal tags, fibroma or condylomata acuminata are easily diagnosed and treated. Secondary perianal eczema requires treatment of the underlying proctologic disease. If it persists, a biopsy is required.