Primary ciliary dyskinesia (PCD) is a clinically rare, genetically and phenotypically heterogeneous condition characterized by chronic respiratory tract infections, male infertility, tympanitis, and laterality abnormalities. PCD is typically resulted from variants in genes encoding assembly or structural proteins that are indispensable for the movement of motile cilia. Here, we identified a novel nonsense mutation, c.466G>T, in cilia- and flagella-associated protein 300 ( CFAP300 ) resulting in a stop codon (p.Glu156*) through whole-exome sequencing (WES). The proband had a PCD phenotype with laterality defects and immotile sperm flagella displaying a combined loss of the inner dynein arm (IDA) and outer dynein arm (ODA). Bioinformatic programs predicted that the mutation is deleterious. Successful pregnancy was achieved through intracytoplasmic sperm injection (ICSI). Our results expand the spectrum of CFAP300 variants in PCD and provide reproductive guidance for infertile couples suffering from PCD caused by them.
Adult ; Female ; Humans ; Male ; Pregnancy ; China ; Ciliary Motility Disorders/genetics* ; Codon, Nonsense ; East Asian People/genetics* ; Exome Sequencing ; Homozygote ; Infertility, Male/genetics* ; Kartagener Syndrome/genetics* ; Pedigree ; Sperm Injections, Intracytoplasmic ; Cytoskeletal Proteins/genetics*

Multiple morphological abnormalities of the flagella (MMAF) represent a severe form of sperm defects leading to asthenozoospermia and male infertility. In this study, we identified a novel homozygous splicing mutation (c.871-4 ACA>A) in the adenylate kinase 7 (AK7) gene by whole-exome sequencing in infertile individuals. Spermatozoa from affected individuals exhibited typical MMAF characteristics, including coiled, bent, short, absent, and irregular flagella. Transmission electron microscopy analysis showed disorganized axonemal structure and abnormal mitochondrial sheets in sperm flagella. Immunofluorescence staining confirmed the absence of AK7 protein from the patients' spermatozoa, validating the pathogenic nature of the mutation. This study provides direct evidence linking the AK7 gene to MMAF-associated asthenozoospermia in humans, expanding the mutational spectrum of AK7 and enhancing our understanding of the genetic basis of male infertility.
Humans ; Male ; Sperm Tail/ultrastructure* ; Homozygote ; Consanguinity ; Asthenozoospermia/pathology* ; Infertility, Male/genetics* ; Mutation ; Pakistan ; Adenylate Kinase/genetics* ; Adult ; Pedigree ; RNA Splicing ; Exome Sequencing ; Spermatozoa

Male infertility can result from impaired sperm motility caused by multiple morphological abnormalities of the flagella (MMAF). Distinct projections encircling the central microtubules of the spermatozoal axoneme play pivotal roles in flagellar bending and spermatozoal movement. Mammalian sperm-associated antigen 17 ( SPAG17 ) encodes a conserved axonemal protein of cilia and flagella, forming part of the C1a projection of the central apparatus, with functions related to ciliary/flagellar motility, skeletal growth, and male fertility. This study investigated two novel homozygous SPAG17 mutations (M1: NM_206996.2, c.829+1G>T, p.Asp212_Glu276del; and M2: c.2120del, p.Leu707*) identified in four infertile patients from two consanguineous Pakistani families. These patients displayed the MMAF phenotype confirmed by Papanicolaou staining and scanning electron microscopy assays of spermatozoa. Quantitative real-time polymerase chain reaction (PCR) of patients' spermatozoa also revealed a significant decrease in SPAG17 mRNA expression, and immunofluorescence staining showed the absence of SPAG17 protein signals along the flagella. However, no apparent ciliary-related symptoms or skeletal malformations were observed in the chest X-rays of any of the patients. Transmission electron microscopy of axoneme cross-sections from the patients showed incomplete C1a projection and a higher frequency of missing microtubule doublets 1 and 9 compared with those from fertile controls. Immunofluorescence staining and Western blot analyses of spermatogenesis-associated protein 17 (SPATA17), a component of the C1a projection, and sperm-associated antigen 6 (SPAG6), a marker of the spring layer, revealed disrupted expression of both proteins in the patients' spermatozoa. Altogether, these findings demonstrated that SPAG17 maintains the integrity of spermatozoal flagellar axoneme, expanding the phenotypic spectrum of SPAG17 mutations in humans.
Humans ; Male ; Infertility, Male/pathology* ; Sperm Tail/ultrastructure* ; Homozygote ; Microtubule-Associated Proteins/genetics* ; Axoneme/genetics* ; Spermatozoa/ultrastructure* ; Adult ; Mutation ; Sperm Motility/genetics* ; Pedigree ; Microtubules ; Microtubule Proteins/genetics*

OBJECTIVES: Uridine diphospho-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) myopathy is a progressive neurodegenerative disease associated with homozygous or compound heterozygous missense mutations in the GNE gene. This study aims to explore the impact of the homozygous p.V543M mutation in on cell phenotype and to gain preliminary insights into the underlying mechanisms. METHODS: Human embryonic kidney 293T (HEK 293T) cells were used to construct wild-type (WT-GNE) and mutant (MUT-GNE) GNE overexpression models. Western blotting and immunofluorescence were used to assess GNE protein expression levels and subcellular localization. Cell adhesion, proliferation, apoptosis, and mitochondrial membrane potential were evaluated using the cell counting kit-8 (CCK-8) assay, crystal violet staining, flow cytometry, Hoechst 33342/propidium iodide (PI) staining, and tetramethylrhodamine ethyl ester (TMRE) staining. Sialic acid synthesis levels and GNE enzymatic activity were measured, and the mRNA expression of sialic acid biosynthesis-related enzymes was quantified by real-time PCR. RESULTS: Western blotting confirmed successful establishment of GNE overexpression models. Immunofluorescence showed significantly reduced co-localization of GNE protein with Golgin-97 in the MUT-GNE group compared to WT-GNE (Pearson's correlation coefficient: 0.65±0.08 vs 0.83±0.06, P<0.05). Compared with WT-GNE, cells in the MUT-GNE group exhibited increased adhesion, decreased proliferation, and reduced mitochondrial membrane potential (P<0.05). No significant differences in apoptosis were observed between groups. The MUT-GNE group showed reduced sialic acid production, significantly decreased kinase activity, and downregulated transcription of sialic acid biosynthesis-related enzymes compared to WT-GNE (P<0.001). CONCLUSIONS The p.V543M mutation in the GNE gene alters cellular phenotype by reducing GNE enzymatic activity and the transcription of sialic acid biosynthesis enzymes, ultimately impairing sialic acid production.
Humans ; Mutation, Missense ; HEK293 Cells ; Apoptosis/genetics* ; Phenotype ; Multienzyme Complexes/metabolism* ; Cell Proliferation ; Homozygote ; Cell Adhesion/genetics* ; Distal Myopathies/genetics*

Cytoskeletal network dysregulation is a pivotal determinant in various immunodeficiencies and autoinflammatory conditions. This report reviews the significance of actin remodeling in disease pathogenesis, focusing on the Arp2/3 complex and its regulatory subunit actin related protein 2/3 complex subunit 1B (ARPC1B). A spectrum of cellular dysfunctions associated with ARPC1B deficiency, impacting diverse immune cell types, is elucidated. The study presents a patient featuring recurrent and persistent eosinophilia attributed to homozygous ARPC1B mutation alongside concomitant compound heterozygous cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. We used ARPC1B antibody to stain the patient's peripheral blood lymphocytes and those of the control. The defect in the ARPC1B gene in the present patient caused absent/low expression by immunofluorescence microscopy. The intricate interplay between cytoskeletal defects and immunological manifestations underscores the complexity of disease phenotypes, warranting further exploration for targeted therapeutic strategies.
Humans ; Actin-Related Protein 2-3 Complex/genetics* ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics* ; Eosinophilia/genetics* ; Homozygote ; Mutation ; Recurrence

Crigler-Najjar syndrome (CNS) and Gilbert syndrome (GS; OMIM: 143500) are rare autosomal recessive diseases that cause unconjugated hyperbilirubinemia due to decreased UGT1A1 enzyme activity. Crigler-Najjar syndrome type 2 (CNS2; OMIM: 606785) increases the risk of gallbladder stone formation and cholecystitis, while GS seldom causes health issues. We found a 28-year-old male patient with recurring right upper abdomen pain who experienced persistent jaundice from birth. CNS2 with gallbladder stones and cholecystitis was diagnosed after genetic testing revealed rare double homozygous mutations A(TA)₇TAA (rs3064744) and P229Q (rs35350960) in the UGT1A1 gene. After pedigree investigation, we found that the patient's parents with modestly increased bilirubin had compound heterozygous mutations A(TA)₇TAA and P229Q, which were GS. Bioinformatics analysis showed that A(TA)₇TAA is in the TATA-box region of the gene UGT1A1 promoter, affecting gene transcriptional initiation, whereas P229Q modifies protein three-dimensional structure and may be harmful. In this pedigree, double homozygous mutations have a more severe phenotype than compound heterozygous mutations. Inherited causes of hyperbilirubinemia should be suspected after ruling out biliary obstruction, and early bilirubin reduction (< 103 µmol/L (6 mg/dL)) may reduce the risk of complications like cholecystitis in CNS2 patients, though further studies with longer follow-up are needed to confirm this observation.
Humans ; Male ; Glucuronosyltransferase/genetics* ; Adult ; Crigler-Najjar Syndrome/complications* ; Cholecystitis/etiology* ; Homozygote ; Mutation ; Pedigree

Objective:To analyze the hearing phenotypes of p. V37I homozygote and compound heterozygote mutation in GJB2 gene, and to provide basis for genetic counseling. Methods:Fifty-three subjects with p. V37I homozygote and compound heterozygote mutation were recruited at Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital from January 2023 to March 2024. All subjects received universal newborn hearing screening（UNHS）, 23-site chip neonatal deafness genetic screening and audiological tests, including ABR, acoustic immittance, DPOAE, ASSR. The results of newborn hearing screening and hearing diagnosis were compared between homozygous mutation group of 30 cases and compound heterozygous mutation group of 23 cases. Results:In 53 cases, the overall refer rate of UNHS was 64.15%（34/53）, the refer rate of homozygous mutation group was 80.00%（24/30）, which was higher than that of compound heterozygous mutation group（43.48%, 10/23）, the difference between the two groups was statistically significant（P<0.05）. Three subjects with p. V37I compound heterozygous mutation had passed UNHS and diagnosed with unilateral mild hearing loss. The average age of diagnosis of 53 cases was （3.77±1.40） months, 25 cases with hearing loss accounted for 47.17%, including 13 cases with unilateral, 12 cases with bilateral, 28 cases with normal hearing accounted for 52.83%. There was no significant difference between homozygous mutation group（56.67%, 17/30） and compound heterozygous mutation group（34.78%, 8/23） in the proportion of confirmed hearing loss（P>0.05）. Among 37 ears of 25 patients with hearing loss, the proportion of mild, moderate and profound hearing loss were 70.27%（26/37）, 27.03%（10/37） and 2.70%（1/37）, respectively. The hearing loss degree of the homozygous mutation group and the compound heterozygous mutation group were mainly mild, accounting for 70.37%（19/27） and 70.00%（7/10） respectively. There was no significant difference between the two groups in the distribution of hearing loss degree（P>0.05）. Conclusion:The probability of hearing loss was 47.17% in infants of GJB2 gene p. V37I homozygote and compound heterozygote mutation, mainly mild hearing loss. There was no difference in the probability of hearing loss and the distribution of hearing loss degree between the two groups. Patients with p. V37I homozygous and compound heterozygous mutation currently diagnosed as normal hearing need continuous clinical follow-up.
Humans ; Connexin 26 ; Heterozygote ; Homozygote ; Female ; Phenotype ; Male ; Mutation ; Connexins/genetics* ; Infant ; Infant, Newborn ; Hearing Tests ; Neonatal Screening ; Deafness/genetics* ; Genetic Testing

OBJECTIVE: To explore the clinical features and genetic variants in two children with neonatal severe hyperparathyroidism (NSHPT). METHODS: Two children who were diagnosed with NSHPT at the Children's Hospital Affiliated to Xi'an Jiaotong University respectively in August 2019 and April 2022 were selected as the study subjects. Clinical data were collected, and both children were subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing. RESULTS: The main clinical features of the two children have included growth delay, hypotonia, hypercalcemia, hypophosphatemia, hyperparathyroid hormonemia, and renal calcium deposition. WES results showed that child 1 has harbored a homozygous c.1378_1G>A splicing variant of the CASR gene, which was unreported previously, whilst child 2 has harbored a homozygous c.2038C>T missense variant of the CASR gene, which was known to be likely pathogenic. Sanger sequencing confirmed that the parents of both children were heterozygous carriers. CONCLUSION The homozygous c.1378_1G>A and c.2038C>T variants of the CASR gene probably underlay the NSHPT in the two children. Discovery of the c.1378_1G>A variant has enriched the mutational spectrum of the CASR gene.
Humans ; Child ; Mutation ; Homozygote

OBJECTIVE: To explore the genetic basis for a patient with early-onset retinitis pigmentosa (RP). METHODS: A patient who had presented at the West China Hospital of Sichuan University on March 10, 2020 was selected as the study subject. The patient and his parents were subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing and in silico analysis. RESULTS: The patient has featured substantial loss of binocular vision field. Funduscopy revealed characteristic bone spicule-type pigment deposits, as well as attenuated retinal arterioles and pale-appearing optic discs. WES revealed that he has harbored compound missense variants of a RP-associated CRB1 gene, including c.2969T>C (p.Leu990Ser) and c.1816T>C (p.Cys606Arg), which were respectively inherited from his father and mother. Homozygous c.1816T>C (p.Cys606Arg) variant has been identified among RP patients, whilst the c.2969T>C (p.Leu990Ser) variant was unreported previously. Both variants were predicted as likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). CONCLUSION The novel compound heterozygous variants of the CRB1 gene probably underlay the early-onset RP in this patient. Above finding has enriched the mutational spectrum of the CRB1 gene.
Male ; Female ; Humans ; China ; Genomics ; Homozygote ; Mothers ; Retinitis Pigmentosa/genetics* ; Eye Proteins/genetics* ; Membrane Proteins/genetics* ; Nerve Tissue Proteins/genetics*

OBJECTIVE: To explore the genetic basis for a child featuring global developmental disorder with epilepsy. METHODS: A child who had presented at Guangzhou Women and Children's Medical Center in July 2022 was selected as the study subject. Clinical data was collected. Potential variant was detected by whole exome sequencing (WES). Candidate variant was validated by Sanger sequencing and bioinformatic analysis. RESULTS: The child, a three-year-old ethnic Zhuang Chinese girl, had presented with global developmental disorder and epilepsy, for which rehabilitation therapy was ineffective. Genetic testing revealed that she has harbored a homozygous c.821T>C (p.Leu274Pro) missense variant of the PIGW gene, for which both of her parents and sister were heterozygous carriers. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as variant of uncertain significance. CONCLUSION The homozygous c.821T>C (p.Leu274Pro) variant of the PIGW gene probably underlay the onset of disease in this child. Above finding has enriched the mutational spectrum of the PIGW gene.
Child, Preschool ; Female ; Humans ; Computational Biology ; Developmental Disabilities ; Epilepsy/genetics* ; Genetic Testing ; Homozygote