Determination of KCNQ1OT1 and H19 methylation levels in BWS and SRS patients using methylation-sensitive high-resolution melting analysis.

Beckwith-Wiedemann syndrome (BWS) and Silver-Russell syndrome (SRS) are caused by imprinting defects on chromosome 11p15.5. Standard diagnostic tests for these syndromes include methylation analysis of the differential methylated regions of the H19 and KCNQ1OT1 genes. Traditionally this has been conducted by Southern blot analysis. PCR-based methods greatly improve the turn around time of the test and require less DNA. One of the newly emerging techniques for SNP genotyping and mutation scanning, high-resolution melting (HRM) analysis, has been shown to be also applicable for methylation analysis. We tested methylation-sensitive HRM analysis as a method for the detection of methylation defects in a group of 16 BWS and SRS patients with known methylation status (determined previously by Southern blotting), as well as 45 normal controls. HRM analysis was able to detect all methylation aberrations in the patients and appeared to be more sensitive than Southern blotting. Variation in normal controls is minimal and the presence of SNPs in the amplified fragment does not influence the outcome of the test. We conclude that methylation-sensitive HRM analysis is a robust, fast, sensitive and cost effective method for methylation analysis in BWS and SRS.