Association between chromosome 6p21 translocation and asthenozoospermia: A retrospective, observational study

Asthenozoospermia (AZS) is the commonest cause of male-related infertility. The patients with AZS easily exhibit infertility, with their wives having spontaneous miscarriages or seeking assisted reproductive treatment. Reciprocal chromosomal translocation (RCT) is an important chromosome structural abnormality and has been reported to affect sperm motility. Genetic counseling for male RCT patients with AZS is still a challenge. This study reported 4 RCT carriers, which were 46,XY,t(1;6) (p36.1;p21), 46,XY,t (6;10) (p21;q11.2), 46,XY,t (6;11) (p21;p15), and 46,XY,t (6;17) (p21;q21), respectively. The association between chromosome 6p21 translocation and AZS is discussed, considering 19 published cases as well. In 6 patients with available semen parameters and 4 patients in this study, all of them were diagnosed with AZS. The SLC26A8 gene and the DNAH8 gene located on chromosome 6p21 are closely related to AZS by gene search using OMIM. For the chromosome 6p21 breakpoint, 72 pathogenic genes were found through the DECIPHER search. Gene ontology analysis showed that these target genes have several molecular functions and are strongly involved in various biological processes. The proteins expressed by these genes are involved in multiple cellular components. These results suggest that the breakpoint of chromosome 6p21 in male RCT carriers is closely related to AZS. The breakpoint may disrupt the structure and function of related genes, resulting in reduced sperm motility. Karyotype analysis should be recommended for AZS patients. Chromosomes and breakpoints involved in RCT should be paid attention to in genetic counseling for patients.