Oligoasthenoteratozoospermia (OAT) is characterized as low sperm count, decreased sperm motility and structural abnormalities of the sperm head in the same patient. However, very few studies reported the genetic alterations associated with OAT. Here we report a 38-year-old patient with OAT from a consanguineous family, with 2-6 million/mL sperm density, 2.1-3.8% normal sperm morphology and immotile sperm. Whole-exome sequencing (WES) identified homozygous variant c.1259A>G:p.Y420C in the TDRD6 gene. TDRD6 is a testis-specific expressed protein that was localized to the chromatoid bodies in germ cells and played an important role in the nonsense-mediated decay pathway. This rare variant co-segregated with the OAT phenotype in this family. Bioinformatic analysis also suggested the variant a pathogenic mutation. Two intracytoplasmic sperm injection (ICSI) cycles were carried out in the patient's wife, but she did not become pregnant after embryo transfer. So the mutations in TDRD6 may be associated with human male infertility and early embryonic lethality.
Keywords: Early embryonic lethality; In-vitro fertilization; Oligoasthenoteratozoospermia; Sperm count; Sperm motility; TDRD6; Whole-exome sequencing.
Copyright © 2018. Published by Elsevier B.V.