Sperm mitochondrial mutations as a cause of low sperm motility.
We report the unique case of a 28-year-old man who, in spite of having a varicocele and a sperm concentration of 5 million/mL, of which 10% were motile and 20% had normal forms (oligoasthenoteratozoospermia [OAT]), was fertile. This was confirmed by paternity testing using 16 autosomal and 6 Y-chromosomal short tandem repeat (STR) loci. An analysis of mitochondrial genes that included cytochrome oxidase I (COI), cytochrome oxidase II (COII), adenosine triphosphate synthase6 (ATPase6), ATPase8, transfer ribonucleic acid (tRNA) serine I, tRNA lysine, and NADH dehydrogenase3 (ND3) revealed, for the first time, 9 missense and 27 silent mutations in the sperm's mitochondrial DNA (mtDNA) but not in the DNA from the blood cells. There was a 2-nucleotide deletion in the mitochondrial COII genes, introducing a stop codon, which might be responsible for low sperm motility.
Centre for Cellular and Molecular Biology, Hyderabad, India.
Kumarasamy
K
Thangaraj
Manjunath B
MB
Joshi
Alla G
AG
Reddy
Avinash A
AA
Rasalkar
Lalji
L
Singh
D000328:Adult; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics; D005260:Female; D006801:Humans; D007248:Infertility, Male / Q000209:etiology*; D008297:Male; D009154:Mutation; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology*; D014646:Varicocele / Q000150:complications
D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV