HSD17B13 truncated variant is associated with a mild hepatic phenotype in Wilson's Disease

HSD17B13 encodes hydroxysteroid 17-β dehydrogenase 13, a novel liver lipid-droplet associated protein that is involved in the regulation of lipid biosynthetic processes. A protein-truncating HSD17B13 variant (rs72613567) was shown to protect individuals from alcoholic and non-alcoholic liver disease. Since steatosis is a common feature in Wilson's disease (WD), we aimed to assess whether the HSD17B13 variant modulates the phenotypic presentation and progression of WD.

METHODS

The HSD17B13:TA (rs72613567) variant was determined by allelic discrimination real-time PCR in 586 patients. The HSD17B13 genotype was correlated with the phenotypic presentation. The age of onset and the type of symptoms at presentation were used as markers of the WD phenotype.

RESULTS

The overall HSD17B13:TA allele frequency in patients with WD was 23.3% (273/1,172), not significantly different from the reported minor allele frequency. There was a significantly lower HSD17B13:TA allele frequency in patients with fulminant WD compared to all other phenotypic WD groups (11.0% vs. 24.0%, p < 0.01). Among the patients with fulminant WD there was a trend for a gender effect; none of the male patients carried the HSD17B13:TA allele. HSD17B13:TA allele frequency was more common in patients with minimal or no fibrosis (49 [31.1%] had simple steatosis and 20 minimal changes at biopsy) than in patients with cirrhosis or advanced fibrosis (22.3%, p = 0.025).

CONCLUSIONS

The HSD17B13:TA allele modulates the phenotype and outcome of WD. This allele likely ameliorates hepatic fibrosis and reduces the transition from copper induced hemolysis to fulminant disease in patients with WD.

LAY SUMMARY

Wilson's disease is a hereditary disease caused by accumulation of copper in the liver and other tissues. It presents with a variety of clinical symptoms. In this study we explored the role of a recently described gene mutation (HSD17B13:TA) which apparently protects the liver against toxins like alcohol. The results indicate that this mutation plays a role in the evolution of liver disease. Patients with Wilson's disease who carry this mutation are more likely to have mild disease, while the absence of the mutation is associated with the most severe form - fulminant Wilson's disease.

Sudden hearing loss in patients with chronic hepatitis C treated with pegylated interferon/ribavirin

BACKGROUND

Sudden hearing loss has been reported on standard interferon (IFN)-alpha2 therapy. This is the first report on the occurrence of sudden hearing loss in six cases of chronic hepatitis C in temporal relation to treatment with pegylated (PEG)-IFN alfa2a or b/ribavirin combination therapy. Three patients were treated in an ongoing randomized placebo-controlled trial comparing the addition of 200 mg amantadine or placebo to the combination of 180 microg PEG-IFN alpha2a (PEGASYS, Roche, Basel, CH)/wk and 1-1.2 g ribavirin/d (COPEGUS, Roche, Nutley, USA) in de novo patients infected with HCV genotype 1. Sudden hearing loss and tinnitus developed on day 1 and after 4, 23, 25, 36, and 40 wk of treatment, respectively.

CONCLUSIONS

Sudden hearing loss may occur in about 1% of patients on PEG-IFN/ribavirin combination therapy. This rate was not different to that observed in an untreated population. Possible mechanisms involved include direct ototoxicity of IFN, autoimmunity, and hematological changes. In contrast to published cases on auditory disability due to standard IFN, hearing loss did not fully resolve after discontinuation of therapy with PEG-IFN. On the other hand, symptoms did not worsen on continued treatment. Therefore, the decision whether to continue or to stop the treatment when signs of ototoxicity appear is based on the clinical judgment of the treating physician.

Combination of interferon induction therapy and ribavirin in chronic hepatitis C

The initial clearance of hepatitis C virus (HCV) during interferon-alfa therapy is dose-dependent. Therefore, higher initial interferon doses (induction therapy) may improve treatment results. This concept was tested in a prospective, randomized controlled trial. Previously untreated patients with chronic hepatitis C were randomized to receive 3 different interferon doses during the first 14 weeks of therapy (Group A, n = 130: 10 MU IntronA [AESCA-Schering Plough, Traiskirchen, Austria]/day for 2 weeks, followed by 10 MU/2 days for 12 weeks; Group B, n = 124: 5 MU/day for 14 weeks; Group C, n = 119; 5 MU/2 days for 14 weeks) followed in all by 5 MU/2 days for 24 weeks. Throughout the whole study all patients received 1 to 1.2 g ribavirin/day. On treatment, no differences in viral clearance rates were observed. Sustained response rates were also not different among the groups (A: 48.5%, B and C: 41.3%, intent to treat). When data were analyzed according to genotypes, sustained response was almost twice as high in patients with genotype 1 receiving high-dose interferon induction therapy (A: 44.2%, B: 28.6%, C: 27%, P <.05). In contrast, results were not different in genotype 3a patients (A: 61.3%, B: 75.9%, C: 56.3%; P >.1). These data indicate that high-dose interferon induction therapy may improve the outcome of interferon/ribavirin combination therapy in genotype 1 patients.