[Utility of denaturing high performance liquid chromatography (DHPLC) for the diagnosis of mevalonate kinase deficiency in periodic disease]

OBJECTIVES: We developed a genetic investigation using denaturing high performance liquid chromatography (DHPLC), in order to identify polymorphisms of the gene MVK in patients with autoinflammatory syndrome suspicion. METHODS: We evaluated 19 patients affected by recurrent fevers and other clinical manifestations usually found in autoinflammatory syndromes and not correlated with infections or autoimmune disease and 10 healthy controls. IgD level was measured in all patients. Molecular testing was performed in DNA extracted from PBMC and MVK gene was analysed either with DHPLC or with automatic sequencer. Primers for PCR amplifications, amplicon lengths and PCR conditions were designed in our laboratory. RESULTS: IgD level was normal in 14 patients. Healthy controls did not show any alteration of the DHPLC-profiles and of the DNA sequences. Twelve patients had at least one altered DHPLC-profile and these data have been confirmed by sequencing. In particular we detected the polymorphisms c.78+61A>G, S52N, S135S, D170D, c.632-18A>G, c.885+24G>A already described in the database INFEVERS. With DHPLC we got the results in shorter time (10 hours/patient) and with lower cost (40 euro/patient) in comparison to direct sequencing (25 hours and 150 euro/patient). CONCLUSIONS: High IgD levels do not represent an essential marker for diagnosis of MKD, as already reported in literature. DHPLC is a rapid low cost technique in order to screen mutations in patients with MKD suspicion. Twelve patients carried at the same time D170D and c.632-18A>G: such event suggests that these SNPs could be in linkage disequilibrium and that such polymorphisms could predispose to MKD.