A novel loss-of-function variant in PNLDC1 inducing oligo-astheno-teratozoospermia and male infertility

Male infertility is a major reproductive disorder, which is clinically characterized by highly heterogeneous phenotypes of abnormal sperm count or quality. To date, five male patients with biallelic loss-of-function (LOF) variants of PARN-like ribonuclease domain-containing exonuclease 1 ( PNLDC1 ) have been reported to experience infertility with nonobstructive azoospermia. The aim of this study was to identify the genetic cause of male infertility with oligo-astheno-teratozoospermia (OAT) in a patient from a Chinese Han family. Whole-exome and Sanger sequencing analyses identified a homozygous LOF variant (NM_173516.2, c.142C>T, p.Gln48Ter) in PNLDC1 . Hematoxylin and eosin staining revealed that the spermatozoa of the patient with OAT had an irregular head phenotype, including microcephaly, head tapering, and globozoospermia. Consistently, peanut agglutinin staining of the spermatozoa revealed a complete or partial loss of the acrosome. Furthermore, the disomy rate of chromosomes in the patient's spermatozoa was significantly increased compared with that of a fertile control sample. We reported an LOF variant of the PNLDC1 gene responsible for OAT.