Frameshift Research Articles

Downregulation of APN1 and ABCC2 mutation in Bt Cry1Ac-resistant Trichoplusia ni are genetically independent.

The resistance to the insecticidal protein Cry1Ac from the bacterium Bacillus thuringiensis (Bt) in the cabbage looper, Trichoplusia ni, has previously been identified to be associated with a frameshift mutation in the ABC transporter ABCC2 gene and with altered expression of the aminopeptidase N (APN) genes APN1 and APN6, shown as missing of the 110-kDa APN1 (phenotype APN1¯) in larval midgut brush border membrane vesicles (BBMV). In this study, genetic linkage analysis identified that the APN1¯ phenotype and the ABCC2 mutation in Cry1Ac-resistant T. ni segregated independently, although they were always associated under Cry1Ac selection. The ABCC2 mutation and APN1¯ phenotype were separated into two T. ni strains respectively. Bioassays of the T. ni strains with Cry1Ac determined that the T. ni with the APN1¯ phenotype showed a low level resistance to Cry1Ac (3.5-fold), and the associated resistance is incompletely dominant in the background of the ABCC2 mutation. Whereas the ABCC2 mutation-associated resistance to Cry1Ac is at a moderate level, and the resistance is incompletely recessive in the genetic background of downregulated APN1. Analysis of Cry1Ac binding to larval midgut BBMV indicated that the midgut in larvae with the APN1¯ phenotype had reduced binding affinity for Cry1Ac, but the number of binding sites remained unchanged, and the midgut in larvae with the ABCC2 mutation had both reduced binding affinity and reduced number of binding sites for Cry1Ac. The reduced Cry1Ac binding to BBMV from larvae with the ABCC2 mutation or APN1¯ phenotype correlated with the lower levels of resistance.IMPORTANCEThe soil bacterium Bacillus thuringiensis (Bt) is an important insect pathogen used as a bioinsecticide for pest control. Bt genes coding for insecticidal proteins are the primary transgenes engineered into transgenic crops (Bt crops) to confer insect resistance. However, the evolution of resistance to Bt proteins in insect populations in response to exposure to Bt threatens the sustainable application of Bt biotechnology. Cry1Ac is a major insecticidal toxin utilized for insect control. Genetic mechanisms of insect resistance to Cry1Ac are complex and require to be better understood. The resistance to Cry1Ac in Trichoplusia ni is associated with a mutation in the ABCC2 gene and also associated with the APN expression phenotype APN1¯. This study identified the genetic independence of the APN1¯ phenotype from the ABCC2 mutation and isolated and analyzed the ABCC2 mutation-associated and APN1¯ phenotype-associated resistance traits in T. ni to provide new insights into the genetic mechanisms of Cry1Ac resistance in insects.

Abstract B029: Repurposing Digital PCR to Diagnose and Create a Novel Genomic Signature for Homologous Recombination Deficiency in Pancreatic Adenocarcinoma

Abstract Introduction: Germline mutations in DNA repair genes are often associated with increased risk of cancer. Mutations that affect the homologous recombination (HR) DNA repair pathway ( e.g., BRCA 1 and BRCA2) are known drivers of pancreatic adenocarcinoma. Early detection relies on identification of pathogenic mutations in patients with a family history of cancer. Next generation sequencing panels often use a select set of pathogenic variants for diagnosis, meaning that individuals with variants of uncertain significance may be missed, limiting testing of other family members for the potentially disease-causing variant. Here we describe a digital PCR assay developed to detect BRCA1 and BRCA2 variant that may eventually serve as a rapid, cost-effective alternative to sequencing that costs less than $5.00 per sample with results in 24 hours. This study highlights the need for better diagnostic tools, which will become critically important as we begin to study pathogenic mutations in more diverse populations. Methods: We have collected blood from 4 BRCA1 mutants and 5 BRCA2 mutants who have already undergone germline sequencing from commercially available assays. Clinicopathologic data has been collected as well. We designed two fluorescently labelled TaqMan probes, one that recognizes the wild-type BRCA alleles and one specific for mutant BRCA alleles. Briefly, 1 ng of genomic DNA is mixed with amplicon primers and fluorescent Taq-Man probes, then partitioned into 20,000 separate 517 picoliter wells. Quantification and detection are achieved based upon the fluorescent signal measured from each well. Results: We have successfully confirmed pathologic BRCA1 and BRCA2 mutations previously identified with next generation sequencing in 100% of samples analyzed. All three BRCA2 mutations generate a premature stop codon leading to a truncated protein and are known to be pathogenic. Two related patients have the same BRCA1 frameshift mutation that results in a premature stop codon, and one patient has a duplicated cytosine that leads to a frameshift mutation that is one of three characterized Ashkenazi Jewish founder mutations that increases cancer risk in this population . Conclusions: Here we report an innovative assay using digital PCR (dPCR) that provides a cost-effective, time-efficient method to identify MMR mutants and characterize VUS in patients and their families. Citation Format: Jennifer Brooke Valerin, Sophie Hasson, Valeria Rangel, Nicholas Pannunzio. Repurposing Digital PCR to Diagnose and Create a Novel Genomic Signature for Homologous Recombination Deficiency in Pancreatic Adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B029.

Frameshift Mutation in the EPB41 Gene with Hereditary Elliptocytosis

Frameshift Mutation in the EPB41 Gene with Hereditary Elliptocytosis

A gain-of-function mutation at the C-terminus of FT-D1 promotes heading by interacting with 14-3-3A and FDL6 in wheat.

Vernalization and photoperiod pathways converging at FT1 control the transition to flowering in wheat. Here, we identified a gain-of-function mutation in FT-D1 that results in earlier heading date (HD), and shorter plant height and spike length in the gamma ray-induced eh1 wheat mutant. Knockout of the wild-type and overexpression of the mutated FT-D1 indicate that both alleles are functional to affect HD and plant height. Protein interaction assays demonstrated that the frameshift mutation in FT-D1eh1 exon 3 led to gain-of-function interactions with 14-3-3A and FDL6, thereby enabling the formation of florigen activation complex (FAC) and consequently activating a flowering-related transcriptomic programme. This mutation did not affect FT-D1eh1 interactions with TaNaKR5 or TaFTIP7, both of which could modulate HD, potentially via mediating FT-D1 translocation to the shoot apical meristem. Furthermore, the 'Segment B' external loop is essential for FT-D1 interaction with FDL6, while residue Y85 is required for interactions with TaNaKR5 and TaFTIP7. Finally, the flowering regulatory hub gene, ELF5, was identified as the FT-D1 regulatory target. This study illustrates FT-D1 function in determining wheat HD with a suite of interaction partners and provides genetic resources for tuning HD in elite wheat lines.

Complete genome sequence of an umbravirus from white snakeroot (Ageratina altissima).

Complete genome sequencing of a virus from a white snakeroot plant (Ageratina altissima (L.) King & H. Rob.) collected in the Great Smoky Mountains National Park, USA, revealed a quadricistronic organization resembling that of umbraviruses. ORFs 1 and 2 are putatively translated via a -1 ribosomal frameshift mechanism as a single polypeptide with a role in viral replication, whereas the 3'-proximal and extensively overlapping ORFs 3 and 4 code for proteins involved in long distance trafficing andcell-to-cell movementwithin the host. Sequence comparisons and phylogenetic analysis strongly suggested that this virus is a previously undescribed member of the genus Umbravirus (family Tombusviridae), for which the name "white snakeroot virus A" (WSVA) is proposed. In addition, we identified and initiated characterization of its possible helper virus, a putative new member of the genus Luteovirus.

SLC12A1 variant c.1684+1 G>A causes Bartter syndrome type 1 by promoting exon 13 skipping.

Bartter syndrome type 1, an autosomal recessive genetic disorder, is caused by pathogenic loss-of-function variants in the SLC12A1 gene. It is characterized by metabolic alkalosis and prenatal-onset polyuria leading to polyhydramnios. We identified pathogenic gene in a 12-day-old newborn boy with Bartter syndrome type 1 using whole-exome sequencing. Sanger sequencing validated the identified variants. A minigene assay was performed to investigate the effect of a novel splice site variant on pre-mRNA splicing. We found a compound heterozygous variants in the SLC12A1 gene, consisting of a known pathogenic missense mutation (NM_000338: c.769 G>A; p.Gly257Ser) and a novel splice site variant (c.1684+1 G>A). In silico predictions and an in vitro minigene splicing assay demonstrated that the splicing variant c.1684+1 G>A abolished a consensus splice donor site of SLC12A1 intron 13, resulting in complete exon 13 skipping, translational frameshift, and premature termination codon, ultimately leading to loss of SLC12A1 function. Using a cell-based in vitro assay, we revealed the aberrant effect of the pathogenic splicing variant SLC12A1 c.1684+1 G>A on pre-mRNA splicing. Our findings expand the gene mutation spectrum of Bartter syndrome type 1, providing a basis for genetic diagnosis and the development of genetic medicines.

Evolution toward extremely high imipenem resistance in Mycobacterium abscessus outbreak strains.

Treatment of Mycobacterium abscessus pulmonary disease requires multiple antibiotics including intravenous β-lactams (e.g., imipenem). M. abscessus produces a β-lactamase (BlaMab) that inactivates β-lactam drugs but less efficiently carbapenems. Due to intrinsic and acquired resistance in M. abscessus and poor clinical outcomes, it is critical to understand the development of antibiotic resistance both within the host and in the setting of outbreaks. We compared serial longitudinally collected M. abscessus subsp. massiliense isolates from the index case of a cystic fibrosis center outbreak and four outbreak-related strains. We found strikingly high imipenem resistance in the later patient isolates, including the outbreak strain (MIC > 512 µg/mL). The phenomenon was recapitulated upon exposure of intracellular bacteria to imipenem. Addition of the β-lactamase inhibitor avibactam abrogated the resistant phenotype. Imipenem resistance was caused by an increase in β-lactamase activity and increased blaMab mRNA level. Concurrent increase in transcription of the preceding ppiA gene indicated upregulation of the entire operon in the resistant strains. Deletion of the porin mspA coincided with the first increase in MIC (from 8 to 32 µg/mL). A frameshift mutation in msp2 responsible for the rough colony morphology and a SNP in ATP-dependent helicase hrpA cooccurred with the second increase in MIC (from 32 to 256 µg/mL). Increased BlaMab expression and enzymatic activity may have been due to altered regulation of the ppiA-blaMab operon by the mutated HrpA alone or in combination with other genes described above. This work supports using carbapenem/β-lactamase inhibitor combinations for treating M. abscessus, particularly imipenem-resistant strains.

Efficacy of PARP inhibitors in advanced high-grade serous ovarian cancer according to BRCA domain mutations and mutation type

ObjectivePreclinical studies have emphasized the potential connection between BRCA specific domains defects and the activity of Poly ADP-ribose polymerase inhibitors (PARPi). Nevertheless, real-world evidence regarding the impact of BRCA domain defects and mutations on PARPi efficacy are limited. The aim of his study was to evaluate the efficacy of PARPi in terms of progression free survival (PFS) according to BRCA domains defects and mutation types.MethodsA retrospective analysis was performed among 79 BRCA mutated patients, diagnosed with advanced High-grade serous ovarian carcinoma (HGSOC) who received first- and second-line platinum- based chemotherapy followed by PARPi maintenance treatment. PFS was evaluated according to BRCA1 [Really Interesting Gene (RING), DNA Binding (DBD), Serine Cluster (SCD), BRCA1 C-terminal (BRCT)] and BRCA2 [RAD-51 Domain (RAD-51 BD), DBD] specific domain defects and mutation types [missense (MS), nonsense (NS), frameshift (FS), splicing (S), or large rearrangements (LR)].ResultsAfter a median follow-up of 51 months, no significant difference in PFS was observed between the BRCA functional domains or mutation types in the BRCA1 and BRCA2 subgroups. Patients with BRCA2 DBD and RAD51-BD defects had the longest (39.8 months) and shortest (24.1 months) median PFS, respectively (p = 0.11). Additionally, patients with BRCA1 DBD defects had the greatest benefit (median PFS = 33.8 months) while those with BRCA1 RING domain mutations experienced the worst outcome (median PFS = 30.9 months (p = 0.43).ConclusionThe efficacy of maintenance treatment with PARPi is independent by BRCA domain defects or mutation types. Patients DBD domain defects experienced numerically longer median PFS compared to those with other BRCA1/2 alterations.

Identification of a novel BAAT frameshift mutation in a female child diagnosed with skeletal dysplasia: A case report.

Skeletal dysplasias are a complex series of rare genetic disorders that cause irregular development of bones, joints, and cartilages in children. A total of 770 disorders associated with 41 groups of skeletal dysplasia have been documented, demonstrating a wide range of clinical manifestations and varying levels of severity. In addition to conventional methods, whole genome sequencing has emerged as a useful approach to pinpointing the underlying etiology of skeletal dysplasias. A 13-month-old female was admitted to the hospital due to the symptoms of jaundice and failure to thrive. The child was subjected to blood tests and a radiographic assessment. The blood chemistries revealed elevated levels of total bilirubin (178 µmol/L), bile acids (198 µmol/L), and low levels of serum calcium (1.69 mmol/L) and phosphate (0.8 mmol/L), along with irregular skeletal development in the forearms and legs, considering rickets and cholestasis. Whole exome sequencing data of the proband revealed a homozygous mutation of c.388dupA in the BAAT (bile acid-CoA: amino acid N-acyltransferase) gene sequence. This mutation caused a frameshift in the amino acid of the BAAT protein, resulting in the pR130Kfs*12 variant. This mutation has been identified as the underlying cause of skeletal dysplasia in the proband. A novel frameshift mutation in the BAAT gene of a Vietnamese female child diagnosed with skeletal dysplasia has been studied by whole exome sequencing analysis. This research reported a case of skeletal dysplasia caused by a frameshift mutation in the BAAT gene. The results of this study contribute to our understanding of the diverse factors that influence irregular skeletal development in children and provide genetic data to support clinical practice.

Charcot-Marie-Tooth type 2CC misdiagnosed as Chronic Inflammatory Demyelinating Polyradiculoneuropathy.

Charcot-Marie-Tooth (CMT) is a heterogeneous group of genetic neuropathies and is typically characterized by distal muscle weakness, sensory loss, pes cavus and areflexia. Herein we describe a case of CMT2CC presenting with proximal muscle weakness and equivocal electrophysiological features, that was misdiagnosed as chronic inflammatory demyelinating polyneuropathy (CIDP). A 30-year-old woman complained of proximal muscle weakness with difficulty climbing stairs. Neurological examination showed weakness in lower limb (LL) muscles, that was marked proximally and mild distally, and absence of deep tendon reflexes in the ankles. Nerve conduction studies (NCS) showed sensory-motor neuropathy with non-uniform NC velocity and a partial conduction block (CBs) in peroneal nerve and tibial nerves. Thus, a diagnosis of CIDP was entertained and the patient underwent ineffective treatment with intravenous immunoglobulins. At electrophysiological revaluation CB in peroneal nerve was undetectable as also distal CMAP had decreased whereas the CBs persisted in tibial nerves. Hypothesizing a hereditary neuropathy, we examined the proband's son, who presented mild weakness of distal and proximal muscles at lower limbs. Neurophysiological investigation showed findings consistent with an intermediate-axonal electrophysiological pattern. A targeted-NGS including 136 CMT genes showed the heterozygous frameshift mutation (c.3057dupG; p.K1020fs*43) in the NEFH gene, coding for the neurofilament heavy chain and causing CMT2CC. Diagnosis of a genetic neuropathy may be challenging when clinical features are atypical and/or electrophysiological features are misleading. The most common misdiagnosis is CIDP. Our report suggests that also CMT2CC patients with proximal muscle weakness and equivocal electrophysiological features might be misdiagnosed as CIDP.

Image encryption algorithm based on a novel cascade chaotic system and DNA mutation

The image is an important medium for information transfer. To ensure image security and improve encryption efficiency, a novel image encryption algorithm is proposed in this paper. Firstly, a new chaotic map is proposed by combining traditional chaotic maps. The SHA-256 algorithm processes the input image to produce chaotic parameters that generate random sequences associated with the plaintext. Secondly, the plain image is encoded using a fast-dynamic DNA encoding method to obtain the DNA matrix. Thirdly, a new DNA sequence operation method called DNA frame shift mutation is designed. The DNA matrix after performing the frame shift mutation transformation is decoded into a pixel matrix. Finally, coordinate matrices are constructed and the pixel positions are randomly selected for dynamic diffusion, which enables simultaneous scrambling and diffusion at the pixel level. The values of the information entropy are all greater than or equal to 7.9993. Experimental results show that the proposed algorithm is secure and it can be resistant to various attacks. Meanwhile, it has sound encryption efficiency.

142P Exploring tumor mutational burden and frameshift mutations as predictors of immune checkpoint inhibitor efficacy

142P Exploring tumor mutational burden and frameshift mutations as predictors of immune checkpoint inhibitor efficacy

Construction and validation of a synthetic phage-displayed nanobody library.

Nanobodies derived from camelids and sharks offer unique advantages in therapeutic applications due to their ability to bind to epitopes that were previously inaccessible. Traditional methods of nanobody development face challenges such as ethical concerns and antigen toxicity. Our study presents a synthetic, phagedisplayed nanobody library using trinucleotide-directed mutagenesis technology, which allows precise amino acid composition in complementarity-determining regions (CDRs), with a focus on CDR3 diversity. This approach avoids common problems such as frameshift mutations and stop codon insertions associated with other synthetic antibody library construction methods. By analyzing FDA-approved nanobodies and Protein Data Bank sequences, we designed sub-libraries with different CDR3 lengths and introduced amino acid substitutions to improve solubility. The validation of our library through the successful isolation of nanobodies against targets such as PD-1, ATXN1 and STAT3 demonstrates a versatile and ethical platform for the development of high specificity and affinity nanobodies and represents a significant advance in biotechnology.

124P Incidence of activating frameshift and nonsense mutations in clinically actionable oncogenes

124P Incidence of activating frameshift and nonsense mutations in clinically actionable oncogenes

Junctional Epidermolysis Bullosa in Sprague Dawley Rats Caused by a Frameshift Mutation of Col17a1 Gene

Junctional epidermolysis bullosa is an intractable cutaneous disorder in humans causing skin fragility and blistering due to mutations in genes encoding essential molecules adhering epidermis and dermis including collagen XVII. However, the pathogenesis still remains to be not fully understood perhaps because of a lack of appropriate animal models. In this study, we report novel mutant rats experiencing junctional epidermolysis bullosa, which was confirmed to be caused by a frameshift mutation of Col17a1 gene, as a rat model for investigating the underlying mechanism of pathogenesis. The mutant rats completely lacked the expression of collagen XVII and had blisters leading to infantile deaths as a homozygous condition, although their skin was apparently normal at birth by light microscopic evaluation except that immunohistochemical examination could not detect collagen XVII in any organs. These observations suggest that collagen XVII is not essential for the development of skin during the prenatal period but is indispensable for keeping epidermal-dermal connections stable after birth. Subsequent electron microscopic examinations further revealed an absence of hemidesmosomal inner plaques being composed of BP230, a binding partner of collagen XVII, and plectin in Col17a1-null newborns, albeit mRNA expressions of these molecules seemed to be unaffected at least during the fetal period. These results suggest that the lack of collagen XVII induces attenuation of hemidesmosomal inner plaques, which in turn destabilizes the epidermis-dermis connection and results in deterioration of epidermal physiology with formation of blisters after birth.

Palmoplantar keratoderma with honeycombing: A case of loricrin keratoderma with heterozygous frameshift mutation in LOR gene, from India

Palmoplantar keratoderma with honeycombing: A case of loricrin keratoderma with heterozygous frameshift mutation in LOR gene, from India

Clinical and molecular findings in children with retinitis pigmentosa

ABSTRACT Purpose To study the clinical and genetic features of a cohort of RP children. Methods We identified 46 RP patients with pathogenic or likely pathogenic mutations among 96 patients with a clinical diagnosis of retinitis pigmentosa. All of the patients underwent comprehensive clinical examinations and genetic testing. A retrospective study was conducted on 46 children with retinitis pigmentosa. The genetic and clinical characteristics of children with different genotypes were analyzed. Results Among the 46 children, 13 inherited X-linked gene mutations, including 9 RPGR and 4 RP2 mutations. There were 10 cases of autosomal dominant genes and 23 cases of autosomal recessive genes. XLRP accounted for a larger proportion of children, as observed in previous studies on RP. We found that RPGR genes were the most commonly mutated genes in RP children. The most frequently mutated gene was RPGR (9.3%), followed by RP2 (4.2%) and RPE65 (4.2%). Forty-six patients had mutations in 21 different genes, 19 of which were novel mutations. Most children with XLRP have a high degree of myopia, poor vision, and severe clinical symptoms. Frameshift mutations were more common in XLRP, followed by nonsense mutations. The onset of XLRP is relatively serious since childhood. Most children with ADRP have relatively good visual acuity and mild clinical symptoms, and missense mutations are common. The clinical manifestations of ARRP in children are more severe than those of ADRP in children but milder than those of XLRP in children, and missense mutations are common. The manifestations of RPE65 mutations are also severe and appear early. Conclusions Our results revealed that XLRP gene mutations were more common in children than in adults, as observed in previous studies on RP. The proportion of RP children with ADRP is relatively small. The new findings in our study polished the spectrum of novel mutations and the proportions of different genotypes in pediatric patients. The onset of XLRP occurred earlier. The genes with a high incidence in children were all relatively severe gene types of RP. This comprehensive database may provide essential information regarding the initial stage of RP.

Helicobacter pylori HP0018 Has a Potential Role in the Maintenance of the Cell Envelope.

Helicobacter pylori is a bacterial pathogen that colonizes the human stomach, where it can cause a variety of diseases. H. pylori uses a cluster of sheathed flagella for motility, which is required for host colonization in animal models. The flagellar sheath is continuous with the outer membrane and is found in most Helicobacter species identified to date. HP0018 is a predicted lipoprotein of unknown function that is conserved in Helicobacter species that have flagellar sheaths but is absent in Helicobacter species that have sheath-less flagella. Deletion of hp0018 in H. pylori B128 resulted in the formation of long chains of outer membrane vesicles, which were most evident in an aflagellated variant of the Δhp0018 mutant that had a frameshift mutation in fliP. Flagellated cells of the Δhp0018 mutant possessed what appeared to be a normal flagellar sheath, suggesting that HP0018 is not required for sheath formation. Cells of the Δhp0018 mutant were also less helical in shape compared to wild-type cells. A HP0018-superfolder green fluorescent fusion protein expressed in the H. pylori Δhp0018 mutant formed fluorescent foci at the cell poles and lateral sites. Co-immunoprecipitation assays with HP0018 identified two enzymes involved in the modification of the cell wall peptidoglycan, AmiA and MltD, as potential HP0018 interaction partners. HP0018 may modulate the activity of AmiA or MltD, and in the absence of HP0018, the unregulated activity of these enzymes may alter the peptidoglycan layer in a manner that results in an altered cell shape and hypervesiculation.

A novel compound heterozygous PCDH15 variants is associated with arRP in a Chinese pedigree

BackgroundRetinitis pigmentosa (RP) is a heterogeneous group of inherited retinal diseases. However, it is still not well understand about the relationship between PCDH15 variants and RP.MethodsIn this study, we enrolled a Chinese autosomal recessive retinitis pigmentosa (arRP) pedigree and identified the causative gene in the proband by targeted whole exome sequencing (WES). The variants were validated in the family members by Sanger sequencing and co-segregation analysis.ResultsNovel compound heterozygous, Frame shift variants of the PCDH15 gene, NM_001384140.1:c.4368 − 2147_4368-2131del and NM_001384140.1:c exon19:c.2505del: p. T836Lfs*6 were identified in the arRP pedigree, which co-segregated with the clinical RP phenotypes. The PCDH15 protein is highly conserved among species.ConclusionThis is the first study to identify novel compound heterozygous variants c.4368 − 2147_4368-2131del and c.2505del(p.T836Lfs*6) in the PCDH15 gene which might be disease-causing variants, and extending the variant spectra. All above findings may be contribute to genetic counseling, molecular diagnosis and clinical management of arRP disease.

A Novel Compound Heterozygous Mutation in TDRD9 Causes Oligozoospermia.

Oligozoospermia is an important cause of male infertility for which treatment options are limited. Spermatogenesis is complex, and the causes of oligozoospermia remain largely unknown. Because genetic mutations are important factors of oligozoospermia pathogenesis, our study aimed to explore the genetic causes of oligozoospermia. Whole- exome sequencing (WES) was performed on one proband from a Chinese family who was diagnosed with oligozoospermia. The pathogenic mutations were confirmed by Sanger sequencing, and a minigene assay was used to determine the effect of the identified splicing mutation. We identified a novel compound heterozygous mutation in the TDRD9 gene, comprising a splicing mutation (c.1115 + 3A > G) and a frameshift mutation (c.958delC), in the proband; neither of these mutations were found in 50 unrelated healthy people. In addition, a minigene assay demonstrated that the frameshift produced partially truncated protein, and the splicing mutation led to a frameshift mutation and premature termination due to abnormal alternative splicing of TDRD9. These findings indicate that deleterious compound heterozygous mutation in TDRD9 could lead to oligozoospermia, highlighting the crucial role of TDRD9 in spermatogenesis and further clarifying the genetic causes of male infertility resulting from oligozoospermia. Our study expands the spectrum of TDRD9-related phenotypes and provides a new specific target for future genetic counseling.