Laboratory Issues

Mutation analysis of the VHL gene is performed as a laboratory-developed test. PCR primers and conditions have been published,8 and probes for Southern blot analysis are available on request from the original researchers.3 Control DNAs for Southern blot analysis are also available from the author on request. There is no organized proficiency-testing program for VHLD; therefore, proficiency testing is performed either by interlaboratory exchange or by repeat testing of samples.

Various sources of DNA are acceptable for testing. Ethylene diamine tetra-acetic acid (EDTA) anticoagulated peripheral blood is the most commonly submitted specimen; however, DNA, frozen tissue, or cultured cells also may be used. Paraffin-embedded tissue, cheek epithelial cells, unspun amniocytes, or direct chorionic villus sampling (CVS) specimens may be used for detecting point mutations by DNA sequence analysis; however, these samples do not provide sufficient quantities of high-molecular-weight genomic DNA for Southern blot analysis.

Mutation screening by Southern blot and DNA sequence analysis is completed in approximately 4 weeks. Interpretation of the assays is fairly straightforward (described above). Point mutations may be compared to an online database of VHL gene mutations in the Universal VHL-Mutation database (www.urnd.be/).11

The mutation detection rate quoted by laboratories in the United States varies from 95% to greater than 99%. Since all laboratories are using the same basic methodologies, this variability is likely due to uncertainty regarding the patient's diagnosis or inadequate clinical information rather than the inability to detect germline mutations in the VHL gene.

References

1. Glenn GM, Choyke PL, Zbar B, Linehan WM. von Hippel-Lindau disease: clinical review and molecular genetics. Probl Urol. 1990;4:312-330.

2. Sgambati MT, Stolle C, Choyke PL, et al. Mosaicism in von Hippel-Lindau disease: lessons from kindreds with germline mutations identified in offspring with mosaic parents. Am J Hum Genet. 2000;66:84-91.

3. Latif F, Tory K, Gnarra J, et al. Identification of the von Hippel-Lindau disease tumor suppressor gene. Science. 1993;260:1317-1320.

4. Kaelin WG Jr. Molecular basis of the VHL hereditary cancer syndrome. Nat Rev Cancer. 2002;2:673-682.

5. Stebbins CE, Kaelin WG Jr, Pavletich NP. Structure of the VHL-elonginC-elonginB complex: implications for VHL tumor suppressor function. Science. 1999;284:455-461.

6. Zbar B, Kishida T, Chen F, et al. Germline mutations in the von Hippel-Lindau disease (VHL) gene in families from North America, Europe and Japan. Hum Mutat. 1996;8:348-357.

7. Hes F, Zewald R, Peeters T, et al. Genotype-phenotype correlations in families with deletions in the von Hippel-Lindau (VHL) gene. Hum Genet. 2000;106:425-431.

8. Stolle C, Glenn G, Zbar B, et al. Improved detection of germline mutations in the von Hippel-Lindau disease tumor suppressor gene. Hum Mutat. 1998;12:417-423.

9. Hoebeeck J, van der Luijt R, Poppe B, et al. Rapid detection of VHL exon deletions using real-time quantitative PCR. Lab Invest. 2005;85: 24-33.

10. Cotton RGH, Scriver CR. Proof of "disease causing" mutation. Hum Mutat. 1998;12:1-3.

11. B eroud C, Joly D, Gallou C, Staroz F, Orfanelli MT, Junien C. Software and database for the analysis of mutations in the VHL gene. Nucleic Acids Res. 1998;26:256-258.

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