DNA mismatch repair gene hMLH3 variants in meiotic arrest

Defects of the DNA mismatch repair gene hMLH3 were screened by denaturing high-performance liquid chromatography and sequencing in germinal tissue DNA from patients with spermatogenic arrest, with sequence variations being confirmed in genomic DNA by polymerase chain reaction (PCR) direct sequencing analysis. Four missense (2896T/C, 2531C/T) and eight intronic (IVS9+66G/A) variants were found, with the combination of 2531C/T and IVS9+66G/A being identified only in patients with primary meiotic arrest, thus suggesting that two simultaneous hMLH3 variants might predispose to spermatogenic arrest.