Four Variants of SLCO2A1 Identified in Three Chinese Patients with Chronic Enteropathy Associated with the SLCO2A1 Gene

A novel variant in the SLCO2A1 gene in a Chinese patient with chronic gastroenteropathy and primary hypertrophic osteoarthropathy

BACKGROUND

Chronic enteropathy associated with SLCO2A1 gene (CEAS) results from loss-of-function variants in SLCO2A1, which encodes the prostaglandin transporter (PGT). CEAS follows an autosomal recessive inheritance pattern. To date, approximate 30 pathogenic variants have been reported in CEAS.

METHODS

We performed whole exome sequencing (WES) to screen for potential pathogenic variants in a patient suspected of having CEAS, and confirmed a variant in SLCO2A1 using Sanger sequencing. We established an in vitro minigene model to compare splicing between wild type (WT) and mutant transcripts. Quantitative polymerase chain reaction (qPCR) was used to evaluate SLCO2A1 transcription in the stomach and colon tissues from the patient and a healthy control (HC). The transcripts were further cloned and sequenced.

RESULTS

The patient had a novel, homozygous, recessive c.929A > G variant in exon 7 of SLCO2A1, which has not been previously reported in CEAS or PHO. This variant altered splicing, resulting in an exon 7-truncated transcript lacking 16 bases. No normal transcript was detected in the patient's stomach or colon tissue. qPCR also showed significantly decreased SLCO2A1 transcription compared to HC.

CONCLUSION

A previously unreported variant caused defective SLCO2A1 splicing and reduced mRNA levels in a patient with CEAS and PHO. This research enhances understanding of CEAS and PHO pathophysiology and aids genetic counseling and diagnosis.

First case report of dichorionic diamniotic twins with chronic enteropathy associated with the SLCO2A1 gene

We report the case of twins diagnosed with chronic enteropathy associated with the SLCO2A1 gene (CEAS) based on characteristic ulcer findings, which required 8 years to diagnose. Both twins had similar symptoms, including anemia and growth failure but the gastrointestinal tract was not evaluated initially because of mild symptoms that were considered consistent with psychological etiology. The endoscopic findings of the firstborn child showed spiral ulcer scars and pseudodiverticulum formation without Helicobacter pylori infection or eosinophilic infiltration in the duodenum. Since the twins presented with ulcers of an unknown cause simultaneously and the first-born child had a spiral ulcer, CEAS was suspected. Genetic analysis and high levels of prostaglandin E major urinary metabolites in the urine led to a definitive diagnosis of CEAS.

Updates on the diagnosis and management of cryptogenic multifocal ulcerative stenosing enteropathy (CMUSE) and non-steroidal enteropathy

Crohn's disease and coeliac disease are well-known to induce ulcerations in the small-bowel. However, there is a group of very rare chronic ulcerative conditions of the small intestine that has emerged from the intestinal black box nearly 70 years ago, and that has gained interest with the advent of small-bowel capsule endoscopy and device-assisted enteroscopy. These distinct ulcerative enteropathies have come to our attention, and continue to reveal their aetiology and treatment options. Two distinct entities, called cryptogenic multifocal ulcerative stenosing enteritis/enteropathy (CMUSE) and chronic nonspecific multiple ulcers of the small intestine (CNSU) are gaining more clinical attention. CMUSE was first reported in Europe, whereas CNSU was exclusively diagnosed in Japanese patients. With the identification of susceptibility genes impacting prostaglandin metabolism, CMUSE and CNSU have become two distinct pathologies within the group of prostaglandin-associated enteropathies, to be differentiated from medication-induced enteropathies, especially non-steroidal anti-inflammatory drugs (NSAID)-induced enteropathy with similar intestinal ulcerations due to interference with prostaglandin metabolism. The current review provides an historical overview of CMUSE and CNSU publications, in addition to the currently available diagnostic and treatment options, and how to differentiate these rare enteropathies from NSAID-induced enteropathy.

Crohn-like disease affecting small bowel due to monogenic SLCO2A1 mutations: First cases of Chronic Enteropathy Associated with SLCO2A1 gene (CEAS) in France

INTRODUCTION

Multiple chronic ulcers of small intestine are mainly ascribed to Crohn's disease. Among possible differential diagnoses are chronic ulcers of small bowel caused by abnormal activation of the prostaglandin pathway either in the archetypal but uncommon non-steroidal anti-inflammatory drug (NSAID)-induced enteropathy, or in rare monogenic disorders due to PLA2G4A and SLCO2A1 mutations. SLCO2A1 variants are responsible for CEAS (Chronic enteropathy associated with SLCO2A1), a syndrome which was exclusively reported in patients of Asian origin. Herein, we report the case of two French female siblings with CEAS.

CASE REPORT

P1 underwent iterative bowel resections (removing 1 meter of small bowel in total) for recurrent strictures and perforations. Her sister P2 had a tight duodenal stricture which required partial duodenectomy. Next-generation sequencing was performed on P1's DNA and identified 2 compound heterozygous variants in exon 12 in SLCO2A1, which were also present in P2.

CONCLUSION

CEAS can be detected within the European population and raise the question of its incidence and recognition outside Asia. Presence of intractable recurrent ulcerations of the small intestine mimicking Crohn's disease with concentric stricture should motivate a genetic search for SLCO2A1 mutations, particularly in the context of family history or consanguinity.

Chronic Enteropathy Associated with Solute Carrier Organic Anion Transporter Family, Member 2A1 (SLCO2A1) with Positive Immunohistochemistry for SLCO2A1 Protein

Chronic enteropathy associated with solute carrier organic anion transporter family, member 2A1 (SLCO2A1) (CEAS) is a rare autosomal recessive hereditary disease characterized by chronic persistent anemia and hypoproteinemia. Its diagnosis typically requires a genetic analysis. The efficacy of immunohistochemical staining with SLCO2A1 polyclonal antibody as a pre-diagnostic tool for CEAS has been previously reported. We herein report a patient with CEAS in whom immunohistochemical staining confirmed SLCO2A1 protein expression. The immunopositive results may have been due to nonsense-mediated RNA decay. As immunohistochemical staining of SLCO2A1 protein may show immunopositive results, a genetic analysis should also be performed when CEAS is strongly clinically suspected.

Immune-mediated inflammatory diseases of the gastrointestinal tract: Beyond Crohn's disease and ulcerative colitis

Immune-mediated inflammatory diseases (IMIDs) are a diverse group of complex inflammatory diseases that result from dysregulated immune pathways and can involve any system of the human body. Inflammatory bowel disease (IBD) is one such disease involving the gastrointestinal (GI) system. With high prevalence in the West and increasing incidence in newly industrialized countries, IBD poses a significant burden on health care. IMIDs of the GI system other than IBD can have similar clinical features, causing diagnostic and therapeutic challenges. Although these disorders share a common pathophysiology, the defects can occur anywhere in the complex network of cytokines, inflammatory mediators, and innate and adaptive systems, leading to unregulated inflammation. Precise knowledge about them will help determine the possible targeted therapy. Thus, it is essential to distinguish these disorders from IBD. This review describes various IMIDs of the GI tract that mimic IBD.