MTHFR promoter hypermethylation in testicular biopsies of patients with non-obstructive azoospermia: the role of epigenetics in male infertility.

BACKGROUND: The causative mechanisms of male infertility are still poorly understood. Mutations in the Methylenetetrahydrofolate reductase (MTHFR) gene have been shown to be involved in male infertility; however, other mechanisms of pathogenesis, like promoter hyper-methylation, could also play a role. Therefore, in this study we compared the methylation status of the promoter region of MTHFR in male patients with non-obstructive azoospermia (NOA) and obstructive azoospermia without anomalies of spermatogenesis. METHODS: DNA from peripheral blood (PB) samples of 50 patients with NOA and 50 fertile men (controls) as well as DNA from testicular biopsies of 32 patients with NOA and five patients with obstructive azoospemia, but normal spermatogenesis, were analyzed by Methylation Specific PCR amplification using primers that hybridize to the CpG island in the promoter region of MTHFR. RESULTS: In PB, no differences in the methylation profile of the promoter region of MTHFR were observed between patients and controls. In testis biopsies, hyper-methylation was detected in 53% of the patients with NOA compared with 0% of patients with obstructive azoospermia (P = 0.03). CONCLUSIONS: These results indicate that hyper-methylation in testis DNA from NOA patients is specific and not due a general methylation defect, and suggest that epigenetic silencing of MTHFR could play a role in azoospermic infertility.

An outbreak of food-borne group A Streptococcus (GAS) tonsillopharyngitis among residents of a dormitory.

Epidemics of food-borne pharyngitis due to group A Streptococcus are rarely reported. Here we present an outbreak of food-borne tonsillopharyngitis in female dormitories in the Islamic Republic of Iran. Throat swabs and cultures were performed on a number of patients, and of specimens from the nasopharynx and hands of staff who were involved in food processing. We planned a case-control study for assessing the source of epidemics. 11 out of 17 throat swabs of students were positive for Streptococcus group A and also 2 throat samples from asymptomatic cooks were positive. A DNA fingerprinting study showed that Streptococcus group A strains of 11 students and 1 cook had the same T agglutination pattern and M protein factor (M3/T13). It is suggested that group A streptococci as well as group C and G streptococci can cause epidemic food-borne pharyngitis. Regular health surveillance of food handlers and food preparation processes are important for prevention of such outbreaks.