Genetic contribution of SUN5 mutations to acephalic spermatozoa in Fujian China.

Acephalic spermatozoa is an extremely rare disease associated with primary infertility. A recent study showed that genetic alterations in the SUN5 gene lead to this disease, and SUN5 mutations could explain the disease in about half of the patients. Therefore, in the present study, to re-visit the genetic contribution of SUN5 mutations to acephalic spermatozoa, we recruited 15 unrelated affected individuals and screened the SUN5 gene for mutations by whole-exome sequencing (WES) and Sanger sequencing. Five of the 15 (33.33%) subjects were found to carry the same homozygous mutation in the SUN5 gene c.381delA (p.V128Sfs*7). Neither homozygous nor compound heterozygous mutations in SUN5 were found in the other 10 patients. The c.381delA mutation resulted in the truncation of the SUN5 protein and decreased the expression and altered the distribution of the outer dense fiber 1 (ODF1) protein. Thus, in our study SUN5 mutations accounted for only one-third of the patients in our cohort, which is lower than the percentage reported previously. Thus, our study suggests that the contribution of SUN5 mutations to acephalic spermatozoa might not be as high as described previously. These results will help in the genetic counseling of patients with acephalic spermatozoa.