Abstract

BACKGROUND: Around 95% of patients with clinical features diagnostic of Von Hippel-Lindau disease (VHL) have a detectable inactivating germline variant in VHL. The VHL protein (pVHL) functions as part of the VCB-CR complex which plays a key role in oxygen sensing and degradation of hypoxia inducible factors. To date, only variants in VHL has been shown to cause VHL disease. MATERIALS AND METHODS: We undertook trio analysis by Whole-exome sequencing (WES) in a proband with VHL disease but without a detectable VHL mutation. Molecular studies were also performed on paired DNA extracted from the proband's kidney tumour and blood and bioinformatics analysis of sporadic renal cell carcinoma data set was undertaken. RESULTS: A de novo pathogenic variant in ELOC (NM_005648.4:c.236A > G [p.Tyr79Cys]) gene was identified in the proband. ELOC encodes elongin C, a key component [C] of the VCB-CR complex. The p.Tyr79Cys substitution is a mutational hotspot in sporadic VHL-competent renal cell carcinoma (RCC) and has previously been shown to mimic the effects of pVHL deficiency on hypoxic signalling. Analysis of a RCC from the proband showed similar findings to that in somatically ELOC mutated RCC (expression of hypoxia responsive proteins, no somatic VHL variants and chromosome 8 loss). CONCLUSIONS: These findings are consistent with pathogenic ELOC variants being a novel cause for VHL disease and suggest that genetic testing for ELOC variants should be performed in individuals with suspected VHL disease with no detectable VHL variant.