[Rapid screening of a hotspot variant c.609G>A in MMACHC gene by using PCR-high-resolution melting curve analysis].

To carry out genetic testing for two families affected with cobalamin C (cblC) and establish a rapid method for the detection of a hotspot pathogenic variant c.609G>A of the MMACHC gene by using a PCR-high-resolution melting curve (PCR-HRM) method.Genomic DNA was extracted from peripheral blood samples of the probands and their parents. Potential variants of the MMACHC gene was analyzed by Sanger sequencing. The c.609G>A variant of the MMACHC gene was screened among 100 healthy children with the PCR-HRM method.Sanger sequencing revealed that proband 1 carried compound heterozygous variants c.394C>T and c.609G>A of the MMACHC gene, while proband 2 carried compound heterozygous variants c.482G>A and c.609G>A of the same gene. PCR-HRM analysis of the two probands and the 100 healthy children were consistent with the Sanger sequencing.c.609G>A is a hotspot pathogenic variant of the MMACHC gene. The diagnosis of cblC may be rapidly attained through detection by PCR-HRM.