Janine Büttner

Hereditary Apolipoprotein AI-Associated Amyloidosis in Surgical Pathology Specimens: Identification of Three Novel Mutations in the APOA1 Gene

Apolipoprotein AI-derived (AApoAI) amyloidosis may present either as a non-hereditary form with wild-type protein deposits in atherosclerotic plaques or as a hereditary form due to germline mutations in the APOA1 gene. Currently, more than 50 apoAI variants are known, and 13 are associated with amyloidosis. We describe six patients with AApoAI amyloidosis due to APOA1 germline mutations that affect the larynx, small intestine, large intestine, heart, liver, kidney, uterus, ovary, or pelvic lymph nodes. In each patient, the amyloid showed a characteristic apple green birefringence when viewed under polarized light after Congo red staining and was immunoreactive with antibodies against apoAI. Sequence analyses revealed one known (p.Leu75Pro) and three novel APOA1 mutations that included gene variations leading to two different frameshifts (p.Asn74fs and p.Ala154fs) and one amino acid exchange (p.Leu170Pro). These three novel mutations extend our knowledge about both the location of the mutations and the organ distribution in hereditary AApoAI amyloidosis. Thirteen of the now sixteen amyloidogenic mutations are localized in two hot-spot regions that span residues 50 to 93 and 170 to 178. The organ distribution and clinical presentation of AApoAI amyloidosis seems to depend on the position of the mutation. Patients with alterations in codons 1 to 75 mostly develop hepatic and renal amyloidosis, while carriers of mutations in residues 173 to 178 mainly suffer from cardiac, laryngeal, and cutaneous amyloidosis.

Heterozygosity for IL23R p.Arg381Gln confers a protective effect not only against Crohn’s disease but also ulcerative colitis

Background  A recent study reported that a non‐synonymous single nucleotide polymorphism (rs11209026, p.Arg381Gln) located in the IL23R gene is a protective marker for inflammatory bowel disease.

Prevalence of germline mutations in the TTR gene in a consecutive series of surgical pathology specimens with ATTR amyloid.

Transthyretin-derived amyloidosis (ATTR) amyloidosis is the third most prevalent amyloid type in surgical pathology and may occur as a hereditary disease with germline mutations in the TTR gene or as senile systemic amyloidosis (SSA) without mutations. Distinction between hereditary ATTR amyloidosis and SSA is of central importance, as the former necessitates genetic counseling and can be treated by liver transplantation. However, little is known about the prevalence of hereditary ATTR amyloidosis in surgical pathology specimens. We have examined the distribution of hereditary ATTR amyloidosis and SSA in a consecutive series of surgical pathology specimens with histologically and immunohistochemically confirmed ATTR amyloid. Thirty-three consecutive patients were retrieved from the Amyloid Registry of the Charité University Hospital. Genomic DNA was extracted from formalin-fixed and paraffin-embedded tissue or patient blood and examined by DNA sequencing. ATTR amyloid was found in the gastrointestinal tract, endomyocardium, peripheral nerve, carpal tunnel ligament, synovia, breast, and testicle. Amyloid fibrils were present as interstitial and vascular deposits, as evidenced by Congo red staining. TTR gene mutations were detected in 12 of 30 patients, with p.Val30Met being the most prevalent (5 patients). Furthermore, 2 novel mutations (p.Asp39Val and p.Glu54Asp) were found. In patients carrying a mutation, ATTR amyloid was found in the gastrointestinal tract, myocardium, nerve, and testicles. To conclude, the hereditary form of ATTR amyloid seems to be more common in elderly patients than previously thought. It is, therefore, important to genetically test every patient when diagnosing ATTR amyloidosis.

The JAK2 variant rs10758669 in Crohn’s disease: altering the intestinal barrier as one mechanism of action

PurposeThe aetiology of intestinal barrier dysfunction in Crohn’s disease (CD) is poorly understood. Associations in relatives of CD families suggest a genetic basis, but the relevant variants are still unknown. We hypothesized that variants in genes occurring in pathways such as autophagy and IL23 signalling might contribute to CD by altering intestinal permeability.MethodsWe analysed five variants (rs10758669 within JAK2, rs744166 within STAT3, rs4958847, rs11747270 and rs13361189 within IRGM) in adult German inflammatory bowel disease patients (CD, n = 464; ulcerative colitis (UC), n = 292) and matched healthy controls (n = 508). These data were correlated with gastrointestinal permeability as assessed by lactulose/mannitol ratio in CD patients (n = 141) in remission.ResultsOur data confirm the association between JAK2 rs10758669 (p = 0.026, OR = 1.25, 95% CI = 1.04–1.50) and STAT3 rs744166 (p = 0.04, OR = 0.83, 95% CI = 0.688–0.998) with CD, but not UC. With respect to all the analysed IRGM variants, no association was found to either CD or UC. Among CD patients, an increased intestinal permeability was detected in 65 out of 141 patients (46.1%). Most importantly, patients carrying the C risk allele within JAK2 rs10758669 displayed an increased permeability more often compared with patients without the C allele (p = 0.004). No association with intestinal permeability was found for STAT3 rs744166 and all IRGM variants.ConclusionsJAK2 rs10758669 and STAT3 rs744166 increase susceptibility for CD. We show that the A>C substitution in rs10758669 of the JAK2 gene is associated with increased intestinal permeability. Altering intestinal barrier function might thus be one mechanism how JAK2 contributes to CD pathogenesis.

Increased small intestinal permeability in ulcerative colitis: Rather genetic than environmental and a risk factor for extensive disease?

Background: A disturbed epithelial barrier could play a pivotal role in ulcerative colitis (UC). We performed a family‐based study analyzing in vivo gastrointestinal permeability in patients with UC, their healthy relatives, spouses, and controls. Methods: In total, 89 patients with UC in remission, 35 first‐degree relatives (UC‐R), 24 nonrelated spouses (UC‐NR), and 99 healthy controls (HC) were studied. Permeability was assessed by a sugar‐drink test using sucrose (gastroduodenal permeability), lactulose/mannitol (intestinal permeability), and sucralose (colonic permeability). Data were correlated with clinical characteristics including medical treatment. Results: Increased intestinal permeability was detected significantly more often in UC patients in remission (25/89, 28.1%) compared with HC (6/99, 6.1%; P < 0.001). Similar results were obtained in UC‐R (7/35, 20.0%; P = 0.01 compared with HC) regardless of sharing the same household with the patients or not. No difference was found between UC‐NR (3/24, 12.5%) and HC. Notably, in UC patients increased intestinal permeability was found in 12/28 patients (42.9%) with pancolitis, 7/30 (23.3%) patients with left‐sided colitis, and in 2/19 (10.5%) patients with proctitis (P = 0.04). Gastroduodenal and colonic permeability were similar in all groups. Among patients on azathioprine, increased intestinal permeability was only seen in 1/18 (5.6%) patients. In contrast, in 24/70 (34.3%) patients without azathioprine, an increased intestinal permeability was found (P = 0.005). Conclusions: An increased intestinal but not colonic permeability was found in UC patients in clinical remission that could mark a new risk factor for extensive disease location. Similar findings in healthy relatives but not spouses suggest that this barrier defect is genetically determined. (Inflamm Bowel Dis 2012)

Mutational analysis of ATP7B gene in Egyptian children with Wilson disease: 12 novel mutations

AbstractThe aim of this work was to study the mutations within ATP7B in Egyptian children with Wilson disease and to evaluate any potential correlation between genotype and phenotype in this cohort. The study consisted of 48 children with Wilson disease from 32 independent families. The 21 exons of the ATP7Bgene were amplified in a thermal cycler. Direct sequencing of the amplified polymerase chain reaction (PCR) products was performed by cycle sequencing using fluorescent dye terminators in an automatic ABI sequencer. Thirty-one different mutations in 96 chromosomes were detected (19 missense, three nonsense, seven frameshift deletions, and two splice-site mutations). Of these, 12 mutations have not been previously reported. The p.N1270S, p.C703Y, IVS18-2A > G, p.R1319X, c.2304-2305insC, and p.H1069Q were present in 7.8%, 6.2%, 6.2%, 6.2%, 4.7%, and 4.7%, respectively, of studied chromosomes in independent families. One patient was homozygous for both p.N1270S and p.T1434M mutations. Frameshift and nonsense mutations were found in 50% of patients with disease onset ≤8 years compared with only 26% in patients with onset >8 years. Despite mutation heterogeneity in Egyptian children, genotype-phenotype correlation analysis seems to be promising in this population, as many patients carry homozygous mutations, a situation that mandates a larger-scale population screening to identify the carrier rate in this community.

No association of the CARD8 (TUCAN) c.30T>A (p.C10X) variant with Crohn's disease: a study in 3 independent European cohorts.

Background: A recent study reported that the c.30T>A (p.Cys10Ter; rs2043211) variant, in the CARD8 (TUCAN) gene, is associated with Crohns disease (CD). The aim of this study was to analyze the frequency of p.C10X in 3 independent European (IBD) cohorts from Germany, Hungary, and the Netherlands. Methods: We included a European IBD cohort of 921 patients and compared the p.C10X genotype frequency to 832 healthy controls. The 3 study populations analyzed were: (1) Germany [CD, n = 317; ulcerative colitis (UC), n = 180], (2) Hungary (CD, n = 149; UC, n = 119), and (3) the Netherlands (CD, n = 156). Subtyping analysis was performed in respect to NOD2 variants (p.Arg702Trp, p.Gly908Arg, c.3020insC) and to clinical characteristics. Ethnically matched controls were included (German, n = 413; Hungarian, n = 202; Dutch, n = 217). Results: We observed no significant difference in p.C10X genotype frequency in either patients with CD or patients with UC compared with controls in all 3 cohorts. Conversely to the initial association study, we found a trend toward lower frequencies of the suggestive risk wild type in CD from the Netherlands compared with controls (P = 0.14). We found neither evidence for genetic interactions between p.C10X and NOD2 nor the C10X variant to be associated with a CD or UC phenotype. Conclusions: Analyzing 3 independent European IBD cohorts, we found no evidence that the C10X variant in CARD8 confers susceptibility for CD.

A study in three European IBD cohorts confirms that the ATG16L1 c.898A > G (p.Thr300Ala) variant is a susceptibility factor for Crohn’s disease

BACKGROUND AND AIMS A recent study reported that a nonsynonymous SNP rs2241880 (c.898A>G, p.Thr300Ala) within ATG16L1 confers susceptibility to Crohns disease (CD). We analyzed ATG16L1 c.898A>G in three independent European inflammatory bowel disease (IBD) cohorts from Germany, Hungary and the Netherlands. METHODS In total, we included 910 European IBD patients and compared the ATG16L1 c.898A>G genotype frequency with 707 ethnically matched healthy controls. We included patients from 3 populations originating from Germany (CD n=310; ulcerative colitis [UC] n=179), Hungary (CD n=147; UC n=117), and the Netherlands (CD n=157). Subtyping analysis was performed in respect to CARD15 alterations and clinical characteristics. RESULTS We found a highly significant association of c.898A>G to CD. The association was significant (p=0.0005) for the total CD cohort but also for the individual populations from Germany (p=0.02) and Netherlands (p=0.02) whereas in the Hungarian CD patients a clear trend was observed (p=0.19; OR 1.227, 95% CI 0.910; 1.654). No association was found between c.898A>G and UC. No statistical interactions were observed between ATG16L1 c.898A>G and CARD15 variants. Furthermore no association to a CD subphenotype was detected. CONCLUSIONS We confirm that ATG16L1 variant c898A>G confers a risk variant for CD but is not associated with a distinct CD phenotype.

Clinical features of hemolysis, elevated liver enzymes, and low platelet count syndrome in undiagnosed Wilson disease: report of two cases.

IntroductionWilson’s disease (WD) is an autosomal recessive disorder characterized by toxic accumulation of copper mainly in the liver and brain. The hepatic manifestation of WD is diverse and may include asymptomatic elevation of aminotransferase, chronic hepatitis, cirrhosis, or acute/fulminant hepatic failure. Characteristic of acute hepatic failure in WD is concomitance of acute intravascular hemolytic anemia that in some patients may represent a first clinical symptom of WD. The diagnosis of acute Wilsonian liver failure is difficult, as similar signs may be observed in other clinical conditions. In pregnant patients with unrecognized WD, liver failure with hemolysis may be interpreted as the low platelet count (HELLP) syndrome.PatientsWe describe two women, who developed the clinical features of hemolysis, elevated liver enzymes, and HELLP syndrome. In both, further diagnostics confirmed WD.ConclusionWD should be remembered in the differential diagnostics of HELLP syndrome.

Effect of caloric restriction on gut permeability, inflammation markers, and fecal microbiota in obese women

Recent findings suggest an association between obesity, loss of gut barrier function and changes in microbiota profiles. Our primary objective was to examine the effect of caloric restriction and subsequent weight reduction on gut permeability in obese women. The impact on inflammatory markers and fecal microbiota was also investigated. The 4-week very-low calorie diet (VLCD, 800 kcal/day) induced a mean weight loss of 6.9 ± 1.9 kg accompanied by a reduction in HOMA-IR (Homeostasis model assessment-insulin resistance), fasting plasma glucose and insulin, plasma leptin, and leptin gene expression in subcutaneous adipose tissue. Plasma high-molecular weight adiponectin (HMW adiponectin) was significantly increased after VLCD. Plasma levels of high-sensitivity C-reactive protein (hsCRP) and lipopolysaccharide-binding protein (LBP) were significantly decreased after 28 days of VLCD. Using three different methods, gut paracellular permeability was decreased after VLCD. These changes in clinical parameters were not associated with major consistent changes in dominant bacterial communities in feces. In summary, a 4-week caloric restriction resulted in significant weight loss, improved gut barrier integrity and reduced systemic inflammation in obese women.