Association between sperm mitochondrial ND2 gene variants and total fertilization failure

Area of Science:

• Reproductive biology
• Human genetics
• Mitochondrial genetics

Background:

• Total fertilization failure (TFF) is a critical issue in assisted reproductive technologies.
• Mitochondrial DNA (mtDNA) plays a crucial role in cellular energy production and sperm function.
• The mitochondrial ND2 (MT-ND2) gene is involved in oxidative phosphorylation, essential for sperm motility and fertilization.

Purpose of the Study:

• To investigate the potential association between sperm mitochondrial ND2 (MT-ND2) gene variants and total fertilization failure (TFF) in in vitro fertilization (IVF).
• To analyze the frequencies of homoplasmic and heteroplasmic variants in the MT-ND2 gene in cases of TFF compared to controls.

Main Methods:

• Retrospective comparative study of 246 fresh IVF/intracytoplasmic sperm injection cycles.
• Inclusion of 59 TFF cases and 187 control cases with normal fertilization.
• Sperm mitochondrial genovariation analysis using nested sequencing to identify MT-ND2 variants and mtDNA haplogroups.

Main Results:

• No significant differences were observed in the frequencies of 32 homoplasmic MT-ND2 variants between TFF and control groups.
• No significant differences were found in the frequencies of specific heteroplasmic variants (4914, 5320, 5426) of the MT-ND2 gene.
• No significant difference in the frequency of mtDNA haplogroup D or G between the IVF failure and normal fertilization groups.

Conclusions:

• The study suggests that variants in the sperm mitochondrial ND2 (MT-ND2) gene are unlikely to be associated with total fertilization failure (TFF).
• Further research may be needed to explore other genetic or non-genetic factors contributing to TFF in IVF.