Using spermatozoa RNA, Yatsenko et al. (2006) screened the candidate gene KLHL10 (608778) by direct sequence analysis in 556 men with oligozoospermia (sperm counts less than 34 million per milliliter), and identified heterozygosity for 1 splice site mutation ... Using spermatozoa RNA, Yatsenko et al. (2006) screened the candidate gene KLHL10 (608778) by direct sequence analysis in 556 men with oligozoospermia (sperm counts less than 34 million per milliliter), and identified heterozygosity for 1 splice site mutation and 2 missense mutations in both mRNA and genomic DNA in 7 patients (608778.0001-608778.0003). Genotyping of 394 controls with completely normal sperm counts revealed that 1 control carried 1 of the missense variants (Q216P; 608778.0001), suggestive of partial penetrance. Functional analysis demonstrated that the missense mutations cause impaired homodimerization of KLHL10, and the splice mutation was predicted to cause premature termination. In addition to oligozoospermia, Yatsenko et al. (2006) observed teratozoospermia in 5 of 7 mutation-positive patients and moderate asthenozoospermia in 4 of them.