Detection of large deletions in the VHL gene using a Real-Time PCR with SYBR Green

Mutation in VHL gene causes the von Hippel-Lindau (VHL) disease, a dominantly inherited familial cancer syndrome. The VHL mutation pattern includes point mutations, small deletions and large deletions. While most mutations can be identified during sequencing, large deletions often remain unnoticed in initial mutational screening. We evaluated the utility of a previously described real-time quantitative PCR (RQ-PCR) using SYBR Green for detection of larger deletions in the VHL gene and normalized the data using two reference genes with a normal copy number i.e., ZNF80 (3q13.31) and GPR15 (3q12.1). DNA sequencing was also done on all cases included in the study. SJNB-6 cell line demonstrating distal 3p loss was used as a positive control for deletion. Out of 21 individual cases included of VHL disease, 2 cases were found with partial deletion by RQ-PCR, with an exon 1 deletion, while PCR-sequencing identified 5 cases with base pair substitution and 1 with splice site variant which were not picked up by RQ-PCR. RQ-PCR proved to be fast, accurate and sensitive for identifying large deletions and can be incorporated into the routine work-up for detection of large deletions in VHL disease.