Common Mitochondrial DNA Mutations Among Infertile Males On Referral to The Korle-Bu Teaching Hospital

ABSTRACT Background:

Studies to find the association between male infertility and mtDNA mutations have been carried out by many researchers but reports from these studies have been varied and contradictory at times. However studies of this nature are scarce in Ghana. The present study has therefore provided a baseline data on mtDNA mutations in relation to male infertility for further studies to be carried out in this area. Main Objective: The overall objective is to ascertain the common mtDNA mutations in the sperm of Ghanaian infertile men referred to Korle-Bu Teaching Hospital, Accra, with the various forms of sperm abnormalities compared to their normospermic counterparts and fertile controls. Design: The study was carried out at the Urology and the Obstetrics and Gynaecology Departments of the KBTH, Accra. Patients referred to these Departments were recruited for the study where their demographic and clinical information was collected by means of a questionnaire. Semen samples were collected from 56 patients and 5 fertile participants as controls. A standard semen analysis was conducted on the samples and was followed by total DNA extraction, amplification and purification of mtDNA from the total DNA after which sequencing was performed using the next generation sequencer (Illimina-MiSeq). Results: The percentage of male infertility due to asthenozoospermia and oligospermia were 1.79% and 5.36% respectively. Majority of the patients, 17 (30.36%) had normal semen parameters, followed by those suffering from oligoasthenoteratozoospermia (16, 28.57%). Poor semen parameters were observed in 16 out of the 23 patients of the study population who are in the habit of drinking alcohol and/or smoking. Thirteen (13) of the patients responded to be either having Gonorrhoea or have treated it and 9 (69.23%) of them were abnormospermic. iv Analysis of the mtDNA revealed a high frequency of nucleotide changes in the infertile males in the genes: 12S rRNA, 16S rRNA, ND2, ND3, ND4, ND5, CO1, CO3, CYTB, and ATPase6. Significant nucleotide changes were observed in the genes: [12S rRNA (nt 750, 1438), 16S rRNA (nt 2706), ATPase6 (nt 8701, 8860), CYTB (nt 14766, 15301, 15326), CO1 (nt 7028), CO3 (nt 9540), ND2 (nt 4769), ND3 (nt 10398), ND4 (nt 10873, 11719), ND5 (nt 12705)] of the infertile males as well as the controls. No mutations were however observed among the patients and controls in the following genes: [TRNL-1(nt 3243), ATPase6 (nt 8821), ND4 (nt 11994)] contrary to what has been reported in other studies. The gene ATPase6 (nt 9055) had only one sample exhibiting the G9055A mutation out of the valid 22 samples. Conclusion: The major cause of infertility among men who are referred to the Urology and the Obstetrics and Gynaecology units of the KBTH is oligoasthenoteratozoospermia with a percentage of 28.57. Infertility due to oligospermia and asthenozoospermia were 5.36% and 1.79% respectively in the study population. A relatively high percentage of (23.21%) of the infertile population were people observed to be suffering from Gonorrhoea or have treated it. The association between mtDNA mutation and male infertility could not be established due to smaller number of controls for an inferential statistical analysis. However it was revealed that the same form of mutations among the infertile population were also observed in the few number of controls used in the study. The type of mutation observed in all the 11 genes analysed in this study was transitional mutation.