OBJECTIVE: To explore the clinical and genetic features of a child with Pontocerebellar hypoplasia type 2B (PCH2B) due to compound heterozygous variants of the TSEN2 gene. METHODS: A PCH2B patient presented at Department of Pediatric Neurology, Xiangya Hospital of Central South University in June 2023 was selected as the study subject. Clinical data of the patient were retrospectively analyzed. The patient and her parents were subjected to whole exome sequencing and bioinformatic analysis. Pathogenicity of the candidate variants were classified based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). A literature review was also conducted by searching the China National Knowledge Infrastructure (CNKI), Wanfang Data, and PubMed databases from their establishment to May 2025 using keywords "TSEN2 gene" "PCH2B" and "Pontocerebellar Hypoplasia 2B" to summarize the clinical and genotypic features of patients with PCH2B due to variants of the TSEN2 gene. This study was approved by the Medical Ethics Committee of the Hospital (No.: #202310892). RESULTS: The patient, a 6-year-5-month-old girl, had exhibited severe global developmental delay, developmental regression, autism spectrum disorder, myoclonus of eyelids, feeding difficulty, irritability, progressive microcephaly, esotropia, and hypotonia. MRI showed reduced volume of bilateral cerebellar hemispheres and vermis. Genetic testing revealed that she has harbored compound heterozygous variants of the TSEN2 gene (NM_025265.4), namely c.1054A>T (p.Lys352*) and c.899G>T (p.Ser300Ile), which were inherited from her father and mother, respectively. Both variants were classified as likely pathogenic based on the ACMG guidelines and were previously unreported. Literature review has identified six PCH2B patients with missense, nonsense, frameshift, and splice site variants of the TSEN2 gene. Their main clinical manifestations included global developmental delay, progressive microcephaly, feeding difficulties, irritability, and vermis hypoplasia. Cranial MRI and genetic testing are crucial for definite diagnosis. CONCLUSION The c.1054A>T (p.Lys352*) and c.899G>T (p.Ser300Ile) compound heterozygous variants of the TSEN2 gene probably underlay the pathogenesis in this patient. Above findings has expanded the genotypic and phenotypic spectra of TSEN2-related PCH2B, and offered guidance for genetic counseling for this family.
Child ; Female ; Humans ; Cerebellar Diseases/genetics* ; Exome Sequencing ; Heterozygote ; Mutation

A 7-year-old girl was admitted to the hospital with rapidly progressive vision loss. Since 1 year of age, she had exhibited developmental delay accompanied by visual impairment and neutropenia. Combined with genetic testing and molecular pathogenicity analysis, she was diagnosed with Cohen syndrome (CS) caused by compound heterozygous variants in VPS13B (c.6940+1G>T and c.2911C>T). The c.6940+1G>T variant resulted in exon 38 skipping, leading to a frameshift and premature termination. Reverse transcription quantitative polymerase chain reaction revealed significantly reduced VPS13B gene expression (P<0.05). Bioinformatic analysis suggested that both variants likely produce truncated proteins. This case highlights that integrating clinical features with molecular pathogenicity assessment (DNA, RNA, and protein analysis) can improve early diagnostic accuracy for CS.
Humans ; Female ; Child ; Vesicular Transport Proteins/genetics* ; Developmental Disabilities/etiology* ; Muscle Hypotonia/etiology* ; Myopia/etiology* ; Heterozygote ; Intellectual Disability/etiology* ; Microcephaly/etiology* ; Obesity/genetics* ; Growth Disorders/etiology* ; Retinal Degeneration/genetics* ; Psychomotor Disorders/genetics* ; Fingers/abnormalities*

OBJECTIVE: To investigate the gene carrier rate and genotype distribution characteristics of thalassemia in the population of Kunming, and compare the differences of red blood cell (RBC) parameters between β⁺ heterozygous carriers, β⁰ heterozygous carriers and healthy population, as well as between different sexes of adults aged 18-45 years. METHODS: A retrospective analysis of 3 195 cases of thalassemia gene screened in the First Affiliated Hospital of Kunming Medical University from April 1, 2020 to March 31, 2022 was performed to detect 21 mutations of β-globin genes which was common in Chinese people using fluorescence PCR melting curve method. Patients with single heterozygous carrying β-thalassemia gene were divided into β⁺ heterozygote group and β⁰ heterozygote group, while the control group consisted of 219 healthy individuals. Four indices, including RBC, hemoglobin (Hb), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) were collected from all β heterozygous carriers and 219 healthy people, and compared between β⁺ heterozygote group, β⁰ heterozygote group and control group, as well as between β⁺ heterozygous carriers, β⁰ heterozygous carriers and healthy population of different sexes aged 18-45 years. RESULTS: There were 688 cases confirmed thalassemia gene carriers, accounting for 21.53%. Among them, 322 cases were found to have β-globin gene mutations, including 145 cases of β⁺ heterozygote, 151 cases of β⁰ heterozygote, and 14 cases of β⁺ homozygotes as well as β⁺ and β⁰ dual heterozygotes. Additionally, 12 cases were found to have simultaneous mutation or deletion of β-globin and α-globin. The carrier rate of CD26 G>A mutation in β⁺ thalassemia was the highest, accounting for 57.9%, while in β⁰ thalassemia CD17 A>T was the highest, accounting for 46.4%. The erythrocyte parameters of 296 β heterozygous mutation carriers were compared with the normal reference interval, and it was found that 218 cases with RBC value greater than the highest value of reference interval, while 105, 281, and 269 cases with Hb, MCV, and MCH value less than the lowest value of reference interval, respectively. There were significant differences in the 4 erythrocyte parameters between β⁺ heterozygotes, β⁰ heterozygotes and healthy individuals (all P < 0.001), and further comparison between different sexes also showed significant differences (all P < 0.001). CONCLUSIONS The carrier rates of thalassemia gene and β-thalassemia heterozygote are both at high level in Kunming, and there are significant differences in the erythrocyte parameters between β⁺ heterozygous carriers, β⁰ heterozygous carriers and healthy individuals. When genetic counseling, it is necessary to inform and strengthen screening among adults of marriageable age to prevent birth of children with severe thalassemia.
Humans ; beta-Thalassemia/blood* ; Adult ; Heterozygote ; Male ; Female ; beta-Globins/genetics* ; Retrospective Studies ; Middle Aged ; Mutation ; Adolescent ; Genotype ; Erythrocytes ; Erythrocyte Indices ; Young Adult ; China ; Genetic Testing ; Asian People/genetics*

OBJECTIVE: The aim of this study is to analyze the clinical features and genetic etiology of a patient with multiple morphological abnormalities of the sperm flagella (MMAF) retrospectively. METHODS: A severely oligospermic patient from the Reproductive Center of the First Affiliated Hospital of Ningbo University was selected as the study subject. Clinical data and examination results were collected. High-throughput sequencing and bioinformatics were used to analyze the genetic etiology. And Sanger sequencing was employed to validate findings in the family. Transmission electron microscopy (TEM) was used to observe the sperm ultrastructure, and immunofluorescence analysis was performed to examine the localization of FSIP2 protein in the sperm. RESULTS: The patient presented with severe oligospermia, and sperm morphology displayed MMAF. TEM revealed fibrous sheath and 9+2 microtubule structural disruptions in the sperm. Sequencing identified compound heterozygous variants in the FSIP2 gene (c.17798C > T, c.5927T > G), inherited from the father and mother, respectively. According to the guidelines of the American College of Medical Genetics and Genomics, the variants were classified as pathogenic. The patient's spouse underwent intracytoplasmic single sperm injection, resulting in one embryo, but no clinical pregnancy occurred after embryo transfer. CONCLUSION This study reported the mutation of FSIP2 gene c.17798C > T, c.5927T > G in a patient with MMAF. These findings expand the mutational spectrum of the FSIP2 gene and provide insights for genetic and assisted reproductive counseling for patients with MMAF.
Humans ; Male ; Sperm Tail/pathology* ; Heterozygote ; Oligospermia/genetics* ; Spermatozoa ; Mutation ; Infertility, Male/genetics* ; Adult ; Pedigree ; Retrospective Studies ; Sperm Injections, Intracytoplasmic

OBJECTIVE: To explore the genetic basis for a woman with oocyte maturation disorder during assisted reproductive treatment (ART), and to verify the source of the variant and its impact on oocyte maturation through family verification. METHODS: A 35-year-old infertile woman presented at the Reproductive Medicine Center of Gansu Provincial Maternal and Child Health Care Hospital on 20 October 2023 for a 10-year history of infertility despite unprotected intercourse was selected as study subject. Peripheral venous blood sample was collected from the proband. Next-generation sequencing (NGS) was used to detect the potential variant. Candidate variants were validated within her family by Sanger sequencing, and their deleteriousness was assessed with comprehensive bioinformatic analyses to elucidate their origin and impact on oocyte maturation. According to the Standards and Guidelines for the Interpretation of Sequence Variants (hereinafter referred to as ACMG Guidelines) formulated by the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of the candidate variant was rated. This study was approved by the Medical Ethics Committee of Gansu Provincial Maternal and Child Health Care Hospital (Ethics No.: 2023GSFYLS78). RESULTS: The proband underwent three controlled ovarian-stimulation cycles as part of assisted reproductive technology, yielding a total of 29 oocytes, among which only three were mature, whilst the remainders exhibited maturation arrest. Targeted sequencing of peripheral-blood DNA revealed a heterozygous c.728C>T (p.P243L) missense variant of the TUBB8 gene. While the same variant was detected in the proband's father. Based on the ACMG guidelines, the variant was classified to be likely pathogenic (PS4_Supporting+PM2_Supporting+PP2+PP3+PP4). CONCLUSION The heterozygous c.728C>T (p.P243L) missense variant of the TUBB8 gene probably underlay the oocyte maturation disorder in the proband, which may be either autosomal dominant or autosomal recessive. For probands with oocyte maturation disorders caused by the heterozygous c.728C>T variant of the TUBB8 gene, oocyte donation may be considered.
Humans ; Female ; Adult ; Mutation, Missense ; Oocytes/metabolism* ; Heterozygote ; Tubulin/genetics* ; Infertility, Female/genetics* ; High-Throughput Nucleotide Sequencing ; Pedigree

OBJECTIVE: To explore the genetic etiology of Pontocerebellar Hypoplasia Type 2D (PCH2D) due to compound heterozygous variants of the SEPSECS gene and to conduct a literature review. METHODS: A child with PCH2D diagnosed at the Children's Hospital of Nanjing Medical University due to "motor and cognitive retardation" in June 2022 was selected as the study subject. Clinical and imaging data were collected. Genomic DNA was extracted from the peripheral blood samples of the child and her parents. Whole-exome sequencing (WES) was conducted using capture-based high-throughput sequencing technology. Candidate variants were confirmed by Sanger sequencing and bioinformatics analysis. The pathogenicity of variant was rated according to the Standards and Guidelines for the Interpretation of Sequence Variants released by American College of Medical Genetics and Genomics (ACMG). Additionally, relevant literature on PCH2D caused by SEPSECS gene variants was reviewed to assess the genotype-phenotype correlation. This study was approved by the Medical Ethics Committee of the hospital (Ethical No.: 202402022-1). RESULTS: The child, a 1-year-and-3-month-old girl, had presented with global developmental delay, progressive microcephaly, hypotonia, elevated blood lactic acid, feeding difficulties, and absent tendon reflexes. Cranial MRI indicated thinning of the splenium of the corpus callosum. Electromyography suggested peripheral neurogenic changes primarily affecting sensory nerves. WES revealed the she has harbored compound heterozygous variants of the SEPSECS gene, namely c.194A>G (p.N65S) and c.896_c.897insA (p.N299fs*2) (NM_016955), which were inherited from her father and mother, respectively. Neither of her parents had related clinical manifestations. According to the ACMG guidelines, the c.194A>G (p.N65S) variant was classified as pathogenic (PM1+PM2_Supporting+PM3+PP3), and the c.896_c.897insA (p.N299fs*2) variant was as likely pathogenic (PVS1+PM2_Supporting). A total of 18 relevant literature were retrieved, which have involved 32 patients (including this case). The p.N65S variant has been reported previously, while the p.N299fs*2 variant is novel. CONCLUSION Compound heterozygous variants in the SEPSECS gene probably underlay the pathogenesis of PCH2D in this child. Above finding has expanded the mutational and phenotypic spectrum of the SEPSECS gene.
Humans ; Female ; Infant ; Heterozygote ; Cerebellar Diseases/genetics* ; Membrane Proteins/genetics* ; Exome Sequencing ; Mutation

OBJECTIVE: To investigate the clinical features and pathogenesis of a child with Stargardt disease caused by variants of ABCA4 gene. METHODS: A child presented at Shenzhen Eye Hospital between September 5, 2020, and April 3, 2023 was selected as the study subject. Clinical data of the child were collected. Whole exome sequencing was performed on peripheral blood samples from the child and his parents. Candidate variants were validated by Sanger sequencing and bioinformatic analysis. This study was approved by the Medical Ethics Committee of Shenzhen Eye Hospital (Ethics No.: 2022KYPJ072). RESULTS: The child was a 10-year-old male presenting with uncorrected visual acuity of 0.1 in both eyes without improvement with refractive correction. Fundus photography showed diffusely distributed yellow-white flecks in the macular region. FAF revealing central hypofluorescence surrounded by a hyperfluorescent ring, and OCT demonstrating significant foveal thinning (right eye: 45 μm; left eye: 50 μm) with ellipsoid zone disruption. Whole exome sequencing and Sanger sequencing revealed that the child has harbored compound heterozygous variants of the ABCA4 gene, namely c.2384G>T (p.Gly795Val) and c.2903G>A (p.Arg968Glu), which were inherited from his phenotypically normal parents and consistent with an autosomal recessive inheritance. This specific combination of the variants was previously unreported. According to the guidelines from the American College of Medical Genetics and Genomics (ACMG) guidelines, both variants were classified as likely pathogenic (PM2_Supporting+PM3+PP3+PP4; PM1+PM2_Supporting+PP3+PP4). CONCLUSION The novel compound heterozygous variants of the ABCA4 gene probably underlay the genetic etiology of Stargardt disease type 1 in this child. Above finding has expanded the mutational spectrum of the ABCA4 gene among the Chinese population and provided further evidence for understanding the genetic heterogeneity and genotype-phenotype correlation of the Stargardt disease.
Humans ; Male ; Child ; ATP-Binding Cassette Transporters/genetics* ; Stargardt Disease/genetics* ; Heterozygote ; Mutation ; Exome Sequencing ; Macular Degeneration/congenital*

OBJECTIVE: To analyze the carrier rates and profiles of pathogenic and likely pathogenic variants for hearing loss-related genes MYO7A, PCDH15, and CDH23 among neonates in Nanjing city through targeted next-generation sequencing (NGS). METHODS: Heel-prick blood samples were collected from 30 043 newborns delivered at Nanjing Women and Children's Health Care Hospital between March 2022 and April 2024. Dried blood spots were prepared, and genomic DNA was extracted. Targeted NGS was applied to detect variants across the full coding regions of the MYO7A, PCDH15, and CDH23 genes. The carrier rates and profiles of pathogenic and likely pathogenic variants of the three genes were analyzed. This study was approved by the Medical Ethics Committee of Nanjing Maternal and Child Health Care Hospital (Ethics No.: 2021KY-071). RESULTS: The carrier rates of pathogenic and likely pathogenic variants (with ≥ 1 variant site) for the MYO7A, PCDH15, and CDH23 genes were 0.340%, 0.226%, and 0.156%, respectively. A total of 65, 49, and 30 variant types were detected in the MYO7A, PCDH15, and CDH23 genes, respectively. For MYO7A, single base variants were predominant, with the most common variant being c.5581C>T, followed by c.1343+1G>A, c.2837T>G, and c.5660C>T, with allelic frequencies of 0.013% (8/60 086), 0.007% (4/60 086), 0.007% (4/60 086), and 0.007% (4/60 086), respectively. PCDH15 variants were mainly deletions, with the most common variant site being c.4699_4715dupAGAGAAAAGATTCAGAG, followed by c.3441delA, c.440T>G, and c.4733_4736delTCAG, with allelic frequencies of 0.015% (9/60 086), 0.005% (3/60 086), 0.005% (3/60 086), and 0.005% (3/60 086), respectively. For CDH23, single base variants were predominant, with c.6604G>A being the most common, followed by c.6085C>T, c.6050+9G>A, and c.6253+1G>A, with allelic frequencies of 0.013% (8/60 086), 0.012% (7/60 086), 0.005% (3/60 086), and 0.005% (3/60 086). CONCLUSION This study analyzed the carrier rates and profiles of pathogenic and likely pathogenic variants of the MYO7A, PCDH15, and CDH23 genes, which can provide more evidence for the prevention and management of deafness in the region.
Humans ; Cadherins/genetics* ; High-Throughput Nucleotide Sequencing/methods* ; Infant, Newborn ; Female ; Myosin VIIa/genetics* ; Cadherin Related Proteins ; Male ; Hearing Loss/genetics* ; Myosins/genetics* ; Heterozygote

OBJECTIVE: To explore the clinical manifestation and genotype of a child with Progressive familial intrahepatic cholestasis 8 (PFIC8) due to variant of KIF12 gene. METHODS: A child diangosed with PFIC8 at Changzhou Children's Hospital in October 2017 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples (3 mL each) were collected from the patient, her parents and younger sister. Following extraction of genomic DNA, whole exome sequencing (WES) was carried out. Candidate variants were validated using Sanger sequencing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of candidate variants was classified. This study has been approved by the Medical Ethics Committee of Changzhou Children's Hospital (Ethics No.: 2023-002). RESULTS: The main clinical manifestations of the child included high GGT cholestasis, portal hypertension, splenomegaly, and abnormal liver enzymes. WES revealed that she has harbored compound heterozygous variants of the KIF12 gene, namely c.245G >A (p.Arg82Gln) and c.1291del (p.Ser431Valfs*13). Bioinformatics analyses showed that both variants were pathogenic. A total of 25 cases were reported in 7 English literature, including 13 males and 12 females. All patients had presented with high GGT cholestasis. Some had progressed to cirrhosis, and 3 cases also had renal lesions. No death was reported. Six children were treated with LTx. Nineteen children were found to harbor homozygous variants of the KIF12 gene, and the remaining six harbored compound heterozygous variants of the same gene. The most common mutation was c.655C>T (p.Arg219*). The mutation sites are mainly located in the Kinesin motor catalytic domain, with high GGT cholestasis as the main clinical feature. No correlation was found between the genotype and phenotype. CONCLUSION PFIC8 caused by KIF12 deficiency is mainly characterized by high GGT cholestasis, for which there is no effective treatment. The c.245G>A and c.1291del compound heterozygous variants of the KIF12 gene probably underlay the pathogenesis in this child.
Humans ; Kinesins/genetics* ; Female ; Cholestasis, Intrahepatic/genetics* ; Phenotype ; Heterozygote ; Child ; Mutation ; Child, Preschool ; Male ; Exome Sequencing

OBJECTIVE: To explore the clinical phenotype and genetic characteristics of a patient with Progressive pseudorheumatoid dysplasia (PPRD) due to compound heterozygous variants of CCN6 gene. METHODS: A patient who was admitted to Qilu Hospital of Shandong University due to "bilateral finger joint deformity, bilateral hip and knee joint movement limitation for 19 years" was selected as the study subject. Clinical data of the patient were retrospectively collected. Peripheral blood samples were collected from the patient and her parents and subjected to whole exome sequencing (WES). Long-read sequencing (LRS) and Sanger sequencing were used to verify the candidate variants. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of candidate variants was classified. This study was approved by the Medical Ethics Committee of Qilu Hospital of Shandong University (Ethics No.: KYLL-202502 061). RESULTS: The patient, a 23-year-old female, presented with progressive polyarticular deformity, limited movement and abnormal growth and development since childhood. She was initially misdiagnosed as Ankylosing spondylitis and had poor response to sulphasalazine and etoricoxib treatment. WES revealed that she has harbored two heterozygous variants of the CCN6 gene (NM_198239.2), namely c.348C>A and c.676G>C. LRS confirmed that the two variants are located on two homologous chromosomes and constitute compound heterozygous variants. Based on the ACMG guidelines, both variants were rated as pathogenic (PVS1+PM2_Supporting+PM3; PM1+PM2_Supporting+PM3_Supporting+PM5+PP3_Strong). The c.676G>C variant has not been recorded by the HGMD and ClinVar databases. CONCLUSION The c.348C>A and c.676G>C compound heterozygous variants of the CCN6 gene probably underlay the pathogenesis of PPRD in this patient. Above finding has enriched the mutational spectrum of PPRD and provided a basis for the clinical diagnosis and genetic counseling.
Humans ; Female ; CCN Intercellular Signaling Proteins/genetics* ; Phenotype ; Heterozygote ; Young Adult ; Mutation ; Exome Sequencing ; Joint Diseases/congenital*