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Background: Multiple morphological abnormalities of the sperm flagella (MMAF), which is characterized as asthenoteratospermia involving absent, short, bent, coiled, and/or irregular‐caliber flagella, is a rare recessive inherited disorder associated with male infertility. To date, genetic causes of MMAF cases are not fully explored. Methods: Whole‐exome sequencing was conducted to identify pathogenic variants in a patient with MMAF. The functional effect of the identified mutations was investigated by immunofluorescence staining and western blotting. Intracytoplasmic sperm injection was used to assist fertilization for the patient with MMAF. Results: We identified novel biallelic mutations, a splicing variant NC_000004.12:g.146937593C>T (c.254+1G>A), and a nonsense mutation NM_001300761.4:c.1185C>G (NP_001287690.1:p.Tyr395*), in TTC29 from an infertile patient. In addition to the typical MMAF phenotype, the patient also presented aberrant morphology of sperm heads. Further functional experiments confirmed the absence of TTC29 expression in the spermatozoa. We also explored the specific expression pattern of TTC29 in human and mouse spermatogenesis. The outcome of intracytoplasmic sperm injection in the patient was unsuccessful, while additional female risk factors should not be excluded. Conclusions: Our study revealed the novel biallelic mutations in TTC29 in a MMAF patient, which findings expand the mutational spectrum of TTC29 and further contribute to the diagnosis, genetic counseling, and prognosis of male infertility. [ABSTRACT FROM AUTHOR]

Male infertility has become a serious health and social problem troubling approximately 15% of couples worldwide; however, the genetic and phenotypic heterogeneity of human infertility poses a substantial obstacle to effective diagnosis and therapy. A previous study reported that heterozygous mutations in solute carrier family 26 member 8 (SLC26A8, NG_033897.1) were causatively linked to asthenozoospermia. Interestingly, in our research, three deleterious heterozygous mutations of SLC26A8 were separately detected in three unrelated patients who were suffered from teratozoospermia. These three heterozygous mutations resulted in the reduction of SLC26A8 expression in transfected cells, while no disrupted expression of SLC26A8 was observed in sperm from the affected individuals. Noticeably, two of the three SLC26A8 heterozygous mutations detected in the patients were inherited from their fertile fathers. Thus, we suggested that male infertility associated with SLC26A8 mutations should be involved in a recessive‐inherited pattern, considering the infertile homozygous Slc26a8 KO male mice, the contribution of heterozygous mutations in SLC26A8 in male infertility needs further deep research. [ABSTRACT FROM AUTHOR]

Centrosomal proteins are necessary components of the centrosome, a conserved eukaryotic organelle essential to the reproductive process. However, few centrosomal proteins have been genetically linked to fertility. Herein we identify a homozygous missense variant of CEP128 (c.665 G > A [p.R222Q]) in two infertile males. Remarkably, male homozygous knock-in mice harboring the orthologous CEP128R222Q variant show anomalies in sperm morphology, count, and motility. Moreover, Cep128 knock-out mice manifest male infertility associated with disrupted sperm quality. We observe defective sperm flagella in both homozygous Cep128 KO and KI mice; the cilia development in other organs is normal—suggesting that CEP128 variants predominantly affected the ciliogenesis in the testes. Mechanistically, CEP128 is involved in male reproduction via regulating the expression of genes and/or the phosphorylation of TGF-β/BMP-signalling members during spermatogenesis. Altogether, our findings unveil a crucial role for CEP128 in male fertility and provide important insights into the functions of centrosomal proteins in reproductive biology. CEP128 is a centrosomal protein important for the organization of centriolar microtubules. Here, the authors show that a CEP128 variant observed in human male siblings causes reduced sperm counts and morphologically abnormal sperm when modeled in mice, suggesting a role for CEP128 in male fertility. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the unknown genetic causes of teratozoospermia, and determine the pathogenicity of candidate variants. Methods: A primary infertile patient and his family members were recruited in the West China Second University Hospital of Sichuan University. Whole-exome sequencing was performed to identify causative genes in a man with teratozoospermia. Immunofluorescence staining and western blotting were applied to assess the pathogenicity of the identified variant. Intracytoplasmic sperm injection (ICSI) was used to assist fertilization for the patient with teratozoospermia. Results: We performed whole-exome sequencing (WES) and detected a novel homozygous frameshift mutation of c.335_336del [p.E112Vfs*3] in DNAJB13 on a primary infertile male patient. Intriguingly, we identified abnormal sperm morphology in this patient, with recurrent respiratory infections and chronic cough. Furthermore, we confirmed that this mutation resulted in negative effects on DNAJB13 expression in the spermatozoa of the affected individual, causing ultrastructural defects in his sperm. Remarkably, our staining revealed that DNAJB13 was expressed in the cytoplasm of primary germ cells and in the flagella of spermatids during spermiogenesis in humans and mice. Finally, we are the first group to report a favorable prognosis using ICSI for a patient carrying this DNAJB13 mutation. Conclusion: Our study revealed a novel homozygous frameshift mutation of c.335_336del [p.E112Vfs*3] in DNAJB13 involved in teratozoospermia phenotype. Our study greatly expands the spectrum of limited DNAJB13 mutations, and is expected to provide a better understanding of genetic counseling diagnoses and subsequent treatment of male infertility. [ABSTRACT FROM AUTHOR]

Purpose: There are limited genes known to cause primary ciliary dyskinesia (PCD)–associated asthenozoospermia. In the present study, we aimed to expand the spectrum of mutations in PCD and to provide new information for genetic counseling diagnoses and the treatment of male infertility in PCD. Methods: One sterile patient with typical situs inversus was recruited to our center, and semen sample was collected. We performed whole-exome sequencing (WES) on the patient to identify the pathogenic mutations associated with PCD and used transmission electron microscopy to investigate spermatozoal ultrastructure. In addition, western blotting and immunofluorescence staining were used to confirm the untoward impact of the variant on the expression of LRRC6, as well as on the dynein arm proteins in the patient's spermatozoa. Results: We identified a homozygous nonsense variant c.749G>A (p.W250*) of LRRC6 in the PCD patient. This variant severely impaired LRRC6 expression and further led to negative effects on dynein arm protein expression in the spermatozoa of the affected individual, which eventually caused defects in sperm ultrastructure and motility. Moreover, we are the first to report a positive prognosis using intracytoplasmic sperm injection (ICSI) for LRRC6-associated male infertility. Conclusions: Our findings strongly implicated the homozygous mutation of c.749G>A (p.W250*) in LRRC6 as a new genetic cause of PCD, uncovering its involvement in defective sperm flagella and poor sperm motility. Furthermore, we posit that patients with LRRC6 mutations may have good outcomes with ICSI treatment. These findings add to the literature on the genetic diagnoses and treatment of male infertility associated with PCD. [ABSTRACT FROM AUTHOR]

• We identified two novel pathogenic mutations in FSIP2 on a MMAF patient. • The patient carrying FSIP2 mutations had poor ICSI prognosis. • Genetic analysis can play a crucial role in FSIP2 diagnosis and prognosis. Multiple morphological abnormalities of the sperm flagella (MMAF) is defined as deformities that cause sperm motility disorders, further resulting in male infertility. However, the reported genes related to sperm flagellar defects can only explain approximately 60% of human MMAF cases. Here, we report two novel compound heterozygous mutations, c.16246_16247insCCCAAATATCACC (p. T5416fs*7) and c.17323C > T (p.Q5774*), in the fibrous sheath-interacting protein 2 gene (FSIP2 ; OMIM: 615796) in an infertile patient by whole-exome sequencing (WES). Western blotting and immunofluorescence staining confirmed that the compound heterozygous mutations abrogated FSIP2 protein expression. Notably, our staining revealed that FSIP2 is expressed in the cytoplasm of primary germ cell and flagella of spermatids during the spermiogenesis. Moreover, intracytoplasmic sperm injection (ICSI) was carried out using sperm from this patient; however, pregnancy failed after embryo transfer through one cycle. Our findings may be helpful in establishing a genetic diagnosis for MMAF, as well as provide additional beneficial knowledge for genetic counseling and infertility treatment. [ABSTRACT FROM AUTHOR]

Testis-specific PRSS55 is a chymotrypsin-like serine protease that is highly conserved among mammalian species. The essential role of Prss55 in mouse male fertility has been established. What is the role of PRSS55 in human reproduction? Whole exome sequencing was used to identify the genetic cause in an infertile male with teratozoospermia. Papanicolaou staining, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to explore morphological defects in the patient's spermatozoa. Immunofluorescence staining and western blot analysis were conducted to assess the pathogenicity of the identified variant. Intracytoplasmic sperm injection (ICSI) was used to assist the patient with fertilization. Sanger sequencing of the pedigree demonstrated that the infertile man carried a novel homozygous mutation in PRSS55 (c.575C>T [p.A192V]). Morphological defects in the sperm head, neck, midpiece and tail were demonstrated by Papanicolaou staining, SEM and TEM. Immunofluorescence staining and western blotting of the patient's spermatozoa showed that the point mutation changed the conformation of PRSS55 and caused a sharp decrease in the PRSS55 protein concentration. The expression and subcellular localization of PRSS55 in the testis and spermatozoa of mice and humans showed that PRSS55 was expressed in the head and flagella of spermatids and epididymal spermatozoa. Moreover, ICSI treatment for this kind of infertile patient was shown to be effective. These findings revealed a novel mutation in PRSS55 in an infertile patient, suggesting for the first time the crucial role of PRSS55 in human fertility. This study provides new insight into genetic counselling diagnoses and subsequent treatment for male infertility. [ABSTRACT FROM AUTHOR]