Rare NOX3 Variants Confer Susceptibility to Agranulocytosis During Thyrostatic Treatment of Graves' Disease.

Agranulocytosis is a rare and serious adverse effect of antithyroid drugs, with unknown etiology. The present study aimed to uncover genetic susceptibility and underlying mechanisms of antithyroid drug-induced agranulocytosis (ATDAC). We studied two independent families with familial Graves' disease, of which several members developed ATDAC. In addition, six sporadic ATDAC patients with Graves' disease were investigated. Whole exome sequencing analysis of affected and unaffected family members was performed to identify genetic susceptibility variants for ATDAC, followed by functional characterization of primary granulocytes from patients and unrelated healthy controls. Whole exome sequencing, cosegregation analysis, and stringent selection criteria of candidate gene variants identified NOX3 as a genetic factor related to ATDAC. Functional studies revealed increased apoptosis of methimazole-treated granulocytes from patients carrying NOX3 variants. In conclusion, genetic variants in NOX3 may confer susceptibility to antithyroid drug-induced apoptosis of granulocytes. These findings contribute to the understanding of the mechanisms underlying ATDAC.

High prevalence of diabetes mellitus in patients with liver cirrhosis.

AIMS: The reported prevalence of Type 2 diabetes mellitus in patients with liver cirrhosis is five times higher than in the general population. However, these data were never adjusted for classical risk factors for Type 2 diabetes. We therefore investigated the association between cirrhosis and Type 2 diabetes and adjusted for known risk factors for Type 2 diabetes. METHODS: We reviewed medical files for presence of Type 2 diabetes and potential confounders in 94 patients with cirrhosis (cases) and compared these with a control group of 107 patients with non-ulcer dyspepsia. Multiple logistic regression analysis was used to adjust for potential confounders. RESULTS: The aetiology of our cirrhosis population was alcohol (59%), viral hepatitis (10%), biliary cirrhosis (3%) or cryptogenic (28%). Prevalence of Type 2 diabetes was significantly higher in patients with cirrhosis than in control subjects: 35/94 (37%) vs. 7/107 (7%) (OR 8.5, 95% CI 3.5­20.2, P < 0.001). After adjustment for age, sex, family history of Type 2 diabetes, alcohol use and BMI, cirrhosis remained significantly associated with Type 2 diabetes (OR 13.6, 95% CI 4.3­42.9, P < 0.001). Most cases of Type 2 diabetes were already diagnosed before diagnosis of cirrhosis (21/35, 60%) or were incidentally found together with cirrhosis (5/35, 14%). CONCLUSIONS: Liver cirrhosis had a strong, independent association with Type 2 diabetes. Classical risk factors such as family history and BMI could not explain the high Type 2 diabetes prevalence in cirrhosis. Therefore, a liver-derived factor might aggravate glucose intolerance and cause Type 2 diabetes in cirrhosis. In addition, Type 2 diabetes might also cause cirrhosis through liver steatosis and fibrosis.

Hepatocyte nuclear factor (HNF)1A and HNF4A substitution occurring simultaneously in a family with maturity-onset diabetes of the young.

INTRODUCTION: Maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes mellitus characterized by an early age at onset, autosomal dominant inheritance and a primary defect in the function of the B-cells of the pancreas. We report a family with two members carrying a substitution in both the hepatocyte nuclear factor (HNF)1A and HNF4A gene simultaneously. CASE REPORT: A 39-year-old man was referred because of mild diabetic retinopathy. Because of a dominant presentation of diabetes in his family, genetic testing was performed. Sequence analysis of the genes involved in MODY-1-3 revealed the presence of an amino acid substitution in the HNF1A as well as the HNF4A gene. Both substitutions were also detected in his mother. The HNF1A substitution has been described previously as pathogenic, whereas the HNF4A substitution had not been found previously. The HNF4A substitution was located in a conserved region of the protein and, additionally, the proband and his mother had high birthweights and low triglyceride levels, both of which are associated with pathogenic HNF4A substitutions. CONCLUSIONS: To our knowledge this is the first reported family carrying both a substitution of HNF1A and HNF4A gene simultaneously. The exact contribution of each substitution to the phenotype of our subjects remains to be further elucidated, however, given the high birthweights and the low triglyceride levels in those with both substitutions, it is reasonable that the HNF4A substitution is pathogenic.