The syndrome of multiple morphological abnormalities of the sperm flagella (MMAF) is one of the most serious kinds of sperm defects, leading to asthenoteratozoospermia and male infertility. In this study, we use whole-exome sequencing to identify genetic factors that account for male infertility in a patient born from a consanguineous Pakistani couple. A homozygous frameshift mutation (c.1399_1402del; p.Gln468ArgfsTer2) in axonemal dynein light chain domain containing 1 ( AXDND1 ) was identified in the patient. Sanger sequencing data showed that the mutation was cosegregated recessively with male infertility in this family. Papanicolaou staining and scanning electron microscopy analysis of the sperm revealed severely abnormal flagellar morphology in the patient. Immunofluorescence and western blot showed undetectable AXDND1 expression in the sperm of the patient. Transmission electron microscopy analysis showed disorganized sperm axonemal structure in the patient, particularly missing the central pair of microtubules. Immunofluorescence staining showed the absence of sperm-associated antigen 6 (SPAG6) and dynein axonemal light intermediate chain 1 (DNALI1) signals in the sperm flagella of the patient. These findings indicate that AXDND1 is essential for the organization of flagellar axoneme and provide direct evidence that AXDND1 is a MMAF gene in humans, thus expanding the phenotypic spectrum of AXDND1 frameshift mutations.
Humans ; Male ; Sperm Tail/ultrastructure* ; Frameshift Mutation ; Infertility, Male/pathology* ; Pakistan ; Pedigree ; Consanguinity ; Axonemal Dyneins/genetics* ; Adult ; Spermatozoa ; Exome Sequencing

OBJECTIVE: To analyze RELT gene mutation found in a pedigree with clinical features and inheritable pattern consistent with amelogenesis imperfecta (AI) in China, and to study the relationship between its genotype and phenotype. METHODS: Clinical and radiological features were recorded for the affected individuals. Peripheral venous blood samples of the patient and family members were collected for further study, and the genomic DNA was extracted to identify the pathogenic gene. Whole exome sequencing (WES) was performed to analyze the possible pathogenic genes, and Sanger sequencing was performed for validation. SIFT and PolyPhen-2 were used to predict and analyze the mutation effect. Comparison of RELT amino acids across different species were performed by using Uniprot website. In addition, the three-dimen-sional structures of the wild type and mutant proteins were predicted by Alphafold 2. RESULTS: The proband exhibited typical hypocalcified AI, with heavy wear, soft enamel, rough and discolored surface, and partial enamel loss, while his parents didn ' t have similar manifestations. WES and Sanger sequencing results indicated that the proband carries a homozygous frameshift mutation in RELT gene, NM_032871.3: c.1169_1170del, and both of his parents were carriers. This mutation was predicted to be pathogenic by SIFT and PolyPhen-2. Up to now, there were 11 mutation sites in RELT gene were reported to be associated with AI, and all of the patients exhibited with hypocalcified AI. Compared with the wild-type RELT protein, the mutant protein p. Pro390fs35 conformation terminated prematurely, affecting the normal function of the protein. CONCLUSION Through phenotype analysis, gene sequencing, and functional prediction of a Chinese family with typical amelogenesis imperfecta, this study found that RELT gene frameshift mutation can lead to protein dysfunction in AI patients. Further research will focus on the role and mechanism of RELT in enamel development at the molecular and animal levels, providing molecular biology evidence for the genetic counseling, prenatal diagnosis, and early prevention and treatment of AI.
Humans ; Amelogenesis Imperfecta/genetics* ; Frameshift Mutation ; Male ; Pedigree ; Female ; China ; Exome Sequencing ; Phenotype ; Adult

OBJECTIVE: To explore the genetic basis for a patient with Dilated cardiomyopathy. METHODS: A patient admitted to Beijing Anzhen Hospital Affiliated to Capital Medical University in April 2022 was selected as the study subject. Clinical data and family history of the patient was collected. Targeted exome sequencing was carried out. Candidate variant was verified by Sanger sequencing and bioinformatic analysis based on guidelines of the American College of Medical Genetics and Genomics (ACMG). RESULTS: DNA sequencing revealed that the patient has harbored a heterozygous c.5044dupG frameshift variant of the FLNC gene. Based on the ACMG guidelines, the variant was predicted to be likely pathogenic (PVS1+PM2_Supporting+PP4). CONCLUSION The heterozygous c.5044dupG variant of the FLNC gene probably underlay the pathogenesis in this patient, which has provided a basis for the genetic counseling for his family.
Humans ; Cardiomyopathy, Dilated/genetics* ; Genetic Testing ; Genetic Counseling ; Computational Biology ; Frameshift Mutation ; Mutation ; Filamins

OBJECTIVE: To explore the genetic basis for a child with mental retardation. METHODS: Whole exome sequencing was carried out for the child. Candidate variant was screened based on his clinical features and verified by Sanger sequencing. RESULTS: The child was found to harbor a c.995_1002delAGACAAAA(p.Asp332AlafsTer84) frameshift variant in the SYNGAP1 gene. Bioinformatic analysis suggested it to be pathogenic. The same variant was not detected in either parent. CONCLUSION The c.995_1002delAGACAAAA(p.Asp332AlafsTer84) frameshift variant of the SYNGAP1 gene probably underlay the mental retardation in this child. Above finding has expanded the spectrum of SYNGAP1 gene variants and provided a basis for the diagnosis and treatment for this child.
Child ; Humans ; Intellectual Disability/genetics* ; Frameshift Mutation ; High-Throughput Nucleotide Sequencing ; Computational Biology ; Heterozygote ; Mutation ; ras GTPase-Activating Proteins/genetics*

Child ; Developmental Disabilities/genetics* ; Frameshift Mutation ; Humans ; Seizures/genetics* ; Seizures, Febrile/genetics* ; Semaphorins/genetics*

OBJECTIVE: To detect the mutation site in a pedigree affected with autosomal dominant polycystic kidney disease (ADPKD) and verify its impact on the protein function. METHODS: Peripheral blood samples were collected from the proband and his pedigree members for the extraction of genomic DNA. Mutational analysis was performed on the proband through whole-exome sequencing. Suspected variant was verified by Sanger sequencing. A series of molecular methods including PCR amplification, restriction enzyme digestion, ligation and transformation were also used to construct wild-type and mutant eukaryotic expression vectors of the PKD2 gene, which were transfected into HEK293T and HeLa cells for the observation of protein expression and cell localization. RESULTS: The proband was found to harbor a c.2051dupA (p. Tyr684Ter) frame shift mutation of the PKD2 gene, which caused repeat of the 2051st nucleotide of its cDNA sequence and a truncated protein. Immunofluorescence experiment showed that the localization of the mutant protein within the cell was altered compared with the wild-type, which may be due to deletion of the C-terminus of the PKD2 gene. CONCLUSION The c.2051dupA (p. Tyr684Ter) mutation of the PKD2 gene probably underlay the pathogenesis of ADPKD in this pedigree.
DNA Mutational Analysis ; Female ; Frameshift Mutation ; HEK293 Cells ; HeLa Cells ; Humans ; Male ; Pedigree ; Polycystic Kidney, Autosomal Dominant/physiopathology* ; Protein Kinases/genetics* ; Protein Transport/genetics* ; Whole Exome Sequencing

OBJECTIVE: To explore the molecular etiology for a Chinese family with mitochondrial DNA depletion syndrome. METHODS: Genomic DNA was extracted from peripheral blood samples of the patient and her parents.Targeted capture and next-generation sequencing was carried out to detect potential variants. Suspected variant was validated by Sanger sequencing. RESULTS: A novel homozygous frameshift variant c.505_508delTATC was identified in the patient, for which both his mother and father were carriers. CONCLUSION The frameshift variant c.505_508delTATC probably underlies the mitochondrial DNA depletion syndrome in this patient. The result also enriched the variant spectrum of DGUOK gene.
Asian Continental Ancestry Group ; genetics ; DNA, Mitochondrial ; genetics ; Female ; Frameshift Mutation ; Humans ; Mutation ; Phosphotransferases (Alcohol Group Acceptor) ; genetics ; Syndrome

OBJECTIVE: To detect potential variant in a male neonate affected with congenital nephrogenic diabetes insipidus (CNDI). METHODS: Clinical data of the patient was collected. Genomic DNA was extracted from peripheral blood samples from the child and his parents. The whole coding regions of the arginine vasopressin V2 receptor (AVPR2) gene were amplified by PCR and subjected to Sanger sequencing. RESULTS: The patient presented recurrent fever and polyuria after birth. Multiple blood gas analyses indicated hypernatremia. Ultrasound showed bilateral hydronephrosis and hydroureter. The patient was partially responsive to hydrochlorothiazide. DNA analysis identified a hemizygous frameshift variant c.890-899delACCCGGAGGC in exon 2 of the AVPR2 gene in the proband. His mother was heterozygous for the same variant. CONCLUSION The c.890-899delACCCGGAGGC variant of the AVPR2 gene probably underlies the CNDI in the child. Above discovery has enriched to spectrum of CNDI associated variants.
Adult ; Diabetes Insipidus, Nephrogenic/genetics* ; Exons ; Female ; Frameshift Mutation ; Humans ; Hydrochlorothiazide/therapeutic use* ; Infant, Newborn ; Male ; Pedigree ; Receptors, Vasopressin/genetics*

OBJECTIVE: To identify the genetic causes of a family with lymphedema-distichiasis syndrome (LDS). METHODS: The whole exome sequencing was performed in a aborted fetus as the proband, and a candidate gene was identified. Peripheral blood of 8 family members were collected. Genotypic-phenotypic analysis were carried out through PCR amplification and Sanger sequencing. RESULTS: The proband, and the mother, grandmother, uncle, granduncle of the proband all had distichiasis or varix of lower limb carried a CONCLUSIONS The
Aborted Fetus/physiopathology* ; Adult ; Eyelashes/pathology* ; Female ; Forkhead Transcription Factors/genetics* ; Frameshift Mutation ; Humans ; Lymphedema/pathology* ; Male ; Phenotype ; Pregnancy ; Whole Exome Sequencing

OBJECTIVE: To identify pathogenic mutation for a family with neurofibromatosis type 1(NF1) and provide prenatal diagnosis for them. METHODS: Mutation analysis of the sporadic family with NF1 was performed with target captured next generation sequencing and Sanger sequencing. RNA samples were extracted from the lymphocytes of NF1 patient and her parents. RT-PCR and Sanger sequencing were performed to analyze the relative mRNA expression in the samples. Prenatal diagnosis of the pathogenic mutation was offered to the fetus. RESULTS: A novel splicing mutation c.1260+4A>T in the gene was found in the proband of the family, but was not found in her parents.cDNA sequencing showed that 13 bases inserted into the 3' end of exon 11 in the gene lead to a frameshift mutation. Prenatal diagnosis suggested that the fetus did not carried the mutant. CONCLUSIONS The : c.1260+4A>T mutation found in the NF1 patient is considered to be pathogenic, which provides information for family genetic counseling and prenatal diagnosis.
DNA Mutational Analysis ; Female ; Frameshift Mutation ; Genetic Testing ; Humans ; Male ; Neurofibromatosis 1 ; diagnosis ; genetics ; Pregnancy ; Prenatal Diagnosis