Autoimmune hepatobiliary disease in trisomy 21

Chromosomal Numerical Aberrations and Rare Copy Number Variation in Patients with Inflammatory Bowel Disease

BACKGROUND AND AIMS

Inflammatory bowel diseases [IBD] have a complex polygenic aetiology. Rare genetic variants can cause monogenic intestinal inflammation. The impact of chromosomal aberrations and large structural abnormalities on IBD susceptibility is not clear. We aimed to comprehensively characterise the phenotype and prevalence of patients with IBD who possess rare numerical and structural chromosomal abnormalities.

METHODS

We performed a systematic literature search of databases PubMed and Embase; and analysed gnomAD, Clinvar, the 100 000 Genomes Project, and DECIPHER databases. Further, we analysed international paediatric IBD cohorts to investigate the role of IL2RA duplications in IBD susceptibility.

RESULTS

A meta-analysis suggests that monosomy X [Turner syndrome] is associated with increased expressivity of IBD that exceeds the population baseline (1.86%, 95% confidence interval [CI] 1.48 to 2.34%) and causes a younger age of IBD onset. There is little evidence that Klinefelter syndrome, Trisomy 21, Trisomy 18, mosaic Trisomy 9 and 16, or partial trisomies contribute to IBD susceptibility. Copy number analysis studies suggest inconsistent results. Monoallelic loss of X-linked or haploinsufficient genes is associated with IBD by hemizygous or heterozygous deletions, respectively. However, haploinsufficient gene deletions are detected in healthy reference populations, suggesting that the expressivity of IBD might be overestimated. One duplication that has previously been identified as potentially contributing to IBD risk involves the IL2RA/IL15R loci. Here we provide additional evidence that a microduplication of this locus may predispose to very-early-onset IBD by identifying a second case in a distinct kindred. However, the penetrance of intestinal inflammation in this genetic aberration is low [<2.6%].

CONCLUSIONS

Turner syndrome is associated with increased susceptibility to intestinal inflammation. Duplication of the IL2RA/IL15R loci may contribute to disease risk.

The Clinical Spectrum of Inflammatory Bowel Disease Associated With Specific Genetic Syndromes: Two Novel Pediatric Cases and a Systematic Review

Background and Aims: Inflammatory bowel disease (IBD) is a typical polygenic disorder and less frequently shows a monogenic origin. Furthermore, IBD can originate in the context of specific genetic syndromes associated with a risk of autoimmune disorders. We aimed to systematically evaluate the prevalence of IBD in specific genetic syndromes and to review the clinical characteristics of the published cases. Methods: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, studies describing patients with IBD and a genetic syndrome and/or studies indicating the prevalence or incidence of IBD in subjects with a genetic syndrome were included. Results: Forty-six studies describing a total of 67 cases of IBD in six genetic syndromes and two personally assessed unpublished cases were included in the review. The majority of cases were associated with Turner syndrome (TS) (38 cases), Down syndrome (DS) (18 cases) and neurofibromatosis type 1 (NF1) (8 cases). Sporadic cases were described in DiGeorge syndrome (2), Kabuki syndrome (2), and Williams syndrome (1). The prevalence of IBD ranged from 0.67 to 4% in TS and from 0.2 to 1.57% in DS. The incidence of IBD was increased in TS and DS compared to the general population. Eight cases of IBD in TS had a severe/lethal course, many of which described before the year 2000. Two IBD cases in DS were particularly severe. Conclusion: Evidence of a greater prevalence of IBD is accumulating in TS, DS, and NF1. Management of IBD in patients with these genetic conditions should consider the presence of comorbidities and possible drug toxicities. Systematic Review Registration: PROSPERO, identifier: CRD42021249820.

Crohn's disease and primary sclerosing cholangitis: a case report and review of the literature

The comorbidity of Crohn's disease (CD) and primary sclerosing cholangitis (PSC) is uncommon. Diagnosing such patients can be difficult, as illustrated by the following case. The combination of CD and PSC should be considered in patients with CD who have abnormal liver function. Because patients with PSC often present asymptomatically, all patients with CD should be screened for PSC by checking serum liver tests. Review of the literature suggests that there is an increased potential in these patients for the development of malignancy and long-term prognosis is poor. We conclude that patients diagnosed with a combination of CD and PSC should be managed with periodic colonoscopy, CA 19-9 investigation, early liver and bowel imaging, and liver biopsy. The treatment of CD associated with PSC remains unsatisfactory and the possibility of liver transplantation should be considered.

Autoantibodies in patients with Down syndrome: early senescence of the immune system or precocious markers for immunological diseases?

AIMS

Down syndrome (DS) patients present several immunological disturbances, with high rates of infections, malignancies and autoimmune phenomena. The present study aims to evaluate the prevalence of autoantibodies in children and adolescents with DS that are not usually investigated, and to establish possible clinical and laboratory associations.

METHODS

One hundred and fifty Caucasoid DS patients from southern Brazil (93M, 57F; median age 4 years) and 105 healthy children (58M, 47F; median age 8 years) were evaluated for the presence of anti-mitochondrial (AMA), smooth-muscle (SMA), liver-kidney microsomal (LKM), nuclear (ANA), gastric parietal cell (GPC) and neutrophil cytoplasmic (ANCA) antibodies, by indirect immunofluorescence, and rheumatoid factor (RF), by turbidimetry.

RESULTS

Forty-three DS patients (28.6%) showed positivity to at least one autoantibody, in comparison with eight of the controls (7.6%; P < 0.001). RF was detected in 28% of the patients and 6.7% of the controls (P < 0.001). ANCA, SMA and ANA were positive in 0.66% of the patients, while AMA, GPC and LKM were negative in all the samples. Currently, none of the RF positive patients has clinical evidence of rheumatic disease.

CONCLUSIONS

Data from the present study suggest that the high incidence of positive RF observed in DS patients might be related to the senescence of the immune system or could be an earlier marker of rheumatic diseases in these patients.

Sclerosing cholangitis

Primary sclerosing cholangitis is a chronic cholestatic disease that may have an autoimmune basis. Most patients have a circulating antineutrophil cytoplasmic antibody that appears to be targeted against a 50-kD nuclear envelope protein. The clinical applications of this antibody have not yet been defined. Other autoantibodies directed against antigens, such as cathepsin G, elastase, and anticardiolipin, may also be detected in some patients. It is suggested that primary sclerosing cholangitis may have a bacterial cause. Helicobacter gene sequences have been detected in liver tissues in primary sclerosing cholangitis. The role of Helicobacter spp and other bacteria in the etiopathogenesis of primary sclerosing cholangitis remains to be determined. Primary sclerosing cholangitis may overlap with autoimmune hepatitis in some cases, although the real prevalence of this association remains to be determined. Many prognostic models have been created, but they lack cross-validation, and their clinical usefulness remains limited. Endoscopic retrograde cholangiography remains the gold standard for diagnosis, but magnetic resonance imaging may be a viable alternative in many cases. Clinical trials with cladibrine, pentoxifylline, and budesonide have failed to demonstrate benefits. Orthotopic liver transplantation remains the only effective treatment.