1.Research progress on the pathogenesis mechanism and therapeutic strategies of DCX mutants.
Xuyan SUN ; Bei LI ; Siyu ZHAO ; Xia LI
Chinese Journal of Medical Genetics 2026;43(1):70-75
The doublecortin (DCX) gene encodes DCX, a microtubule-associated protein that plays a crucial role in brain development. DCX variants can disrupt microtubule binding and stabilization, interfere with intracellular transport, and affect post-translational modifications. A correlation exists between variant types and clinical severity. Animal models and induced pluripotent stem cell (iPSC) models simulating DCX deficiency revealed the dynamic progression of the disease, which has provided a powerful tool for investigating disease mechanisms and screening therapeutic agents. Currently there is no cure for DCX variants, with treatment primarily relying on anti-epileptic drugs and symptom management. Basic research is now offering new avenues for future therapeutic approaches. This article has summarized the potential pathogenic mechanisms and therapeutic strategies for the DCX variants, with an aim to provide insights for clinical treatment.
Humans
;
Doublecortin Protein
;
Doublecortin Domain Proteins
;
Animals
;
Neuropeptides/metabolism*
;
Microtubule-Associated Proteins/metabolism*
;
Mutation
2.Clinical efficacy analysis of seven pediatric patients with Acute myeloid leukemia and the t(16;21)(p11;q22) FUS::ERG fusion gene.
Lihuan SHI ; Shan HUANG ; Xing XIE ; Pengkai FAN ; Haili GAO ; Yanna MAO
Chinese Journal of Medical Genetics 2026;43(2):90-95
OBJECTIVE:
To analyze the clinical characteristics, treatment, and prognosis of seven pediatric patients with Acute myeloid leukemia (AML) positive for the t(16;21)(p11;q22) FUS::ERG fusion gene.
METHODS:
A retrospective analysis was carried out on the clinical data, treatment, and prognosis of seven AML patients with t(16;21)(p11;q22) FUS::ERG fusion gene admitted to Henan Children's Hospital between June 2015 and November 2024. Relevant literature was also reviewed. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: 2024-102-001).
RESULTS:
Among 297 pediatric patients with AML, 7 cases (2.36%) were positive for the t(16;21)(p11;q22) FUS::ERG fusion gene, including 3 males and 4 females, with a median age of 11 years (range: 3 ~ 12 years). According to the FAB classification, these included 1 case of M2, 3 cases of M5, and 3 cases of AML-not otherwise specified (non-M3). All 7 patients were found to harbor the t(16;21)(p11;q22) translocation, with 3 cases showing additional chromosomal abnormalities. Immunophenotyping revealed universal expression of CD13, CD33, CD34, and CD117, with partial expression of CD56, CD4, CD64, CD123, CD15, CD38, CD11b, HLA-DR, cMPO, and CD16. One patient achieved complete remission (CR) after the first course of DAE (cytarabine + daunorubicin + etoposide) induction chemotherapy but relapsed and discontinued the treatment. Six patients received DAH (cytarabine + daunorubicin + homoharringtonine) induction therapy, of whom 2 achieved CR after two courses and underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), resulting in an overall CR rate of 42.86%. Five children did not receive allo-HSCT and had a median overall survival of 9 months (range: 6 ~ 18 months). Two children who underwent transplantation achieved bone marrow morphological and molecular biological relapse at 6 and 9 months post-transplantation, respectively. After receiving combined chemotherapy and donor lymphocyte infusion, one child failed to achieve remission and died at 22 months post-transplantation, while the other has been followed up to date with positive fusion gene status. Their overall survival was 25 months and 30 months, respectively.
CONCLUSION
The t(16;21)(p11;q22) FUS::ERG fusion gene is rare in pediatric AML and associated with poor prognosis. Allo-HSCT may mitigate the adverse prognostic impact of the FUS::ERG fusion gene and contribute to prolonged survival.
Humans
;
Male
;
Child
;
Female
;
Leukemia, Myeloid, Acute/drug therapy*
;
Oncogene Proteins, Fusion/genetics*
;
Translocation, Genetic
;
Retrospective Studies
;
RNA-Binding Protein FUS/genetics*
;
Chromosomes, Human, Pair 16/genetics*
;
Adolescent
;
Child, Preschool
;
Chromosomes, Human, Pair 21/genetics*
;
Prognosis
;
Treatment Outcome
3.Analysis of a three-generation Chinese pedigree affected with Hereditary spastic paraplegia type 3A due to variant of ATL1 gene.
Zhenhua GONG ; Fengjuan HE ; Changshui CHEN ; Yu AN
Chinese Journal of Medical Genetics 2026;43(2):129-135
OBJECTIVE:
To explore the genetic basis for a Chinese pedigree affected with Hereditary spastic paraplegia type 3A (SPG3A) and the genotype-phenotype correlation.
METHODS:
A three-generation pedigree presented at Huantai Maternal and Child Health Care Hospital in March 2021 was selected as the study subject. Whole-exome sequencing (WES) and pedigree analysis was carried out. Candidate variant was validated by Sanger sequencing of the members from the pedigree. Haplotype analysis was used to trace the origin of the variant, and pathogenicity was rated based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: 2025-12).
RESULTS:
A c.1024C>T (p.Pro342Ser) variant of the ATL1 was identified in the four affected members, including the proband, but none of the three unaffected relatives. Haplotype analysis suggested that the variant was derived from the proband's mother and has co-segregated with the disease phenotype. Based on the guidelines of the ACMG, it was classified as likely pathogenic.
CONCLUSION
The ATL1 c.1024C>T (p.Pro342Ser) variant probably underlay the pathogenesis in this pedigree. Above finding has enriched the mutational spectrum of ATL1 and phenotypic spectrum of SPG3A in the Chinese population, and enabled genetic counseling for this pedigree.
Humans
;
Pedigree
;
Spastic Paraplegia, Hereditary/genetics*
;
Male
;
Female
;
Asian People/genetics*
;
Adult
;
Haplotypes
;
Membrane Proteins/genetics*
;
Exome Sequencing
;
GTP-Binding Proteins/genetics*
;
Mutation
;
Middle Aged
;
China
;
Genetic Association Studies
;
East Asian People
4.Clinical phenotype and genetic analysis of a child with Autosomal dominant intellectual developmental disorder type 5 caused by SYNGAP1 gene variant: A case report and literature review.
Zihao WANG ; Lifen DUAN ; Zhangxiang WANYAN ; Ruixi TAO ; Weitao YE ; Zhaoqing YANG
Chinese Journal of Medical Genetics 2026;43(3):213-219
OBJECTIVE:
To delineate the clinical and genetic features of a Chinese girl harboring a rare de novo variant of SYNGAP1 associated with Mental retardation, autosomal dominant 5 (MRD5), and to conduct a comprehensive genotype-phenotype correlation analysis within the Chinese population through an extensive literature review.
METHODS:
A 5-year-old girl presenting with seizures without an obvious cause was enrolled in September 2020. Genomic DNA was extracted from the patient and her parents. Whole exome sequencing (WES) was performed on the proband to identify suspected pathogenic variants based on her clinical phenotype. Sanger sequencing was used for validation, followed by bioinformatic analysis of the variant. Additionally, data from 54 previously reported Chinese cases with SYNGAP1 variants were integrated to summarize the distribution of variant types and clinical characteristics. Ethical approval was obtained from the Ethics Committee of Kunming Children's Hospital (Ethics No.: 2021-03-055-K01).
RESULTS:
WES identified a heterozygous nonsense variant, SYNGAP1 c.725G>A (p.Trp242*), in the proband. Sanger sequencing confirmed it was a de novo variant. According to the ACMG guidelines, this variant was classified as pathogenic (PVS1+PS2). Based on the clinical manifestations, the patient was diagnosed with MRD5. Bioinformatic analysis suggested that this variant introduces a premature stop codon at tryptophan 242, disrupting the PH domain and leading to the loss of the C2, Ras-GAP, and C-terminal domains. The pooled analysis of Chinese cases revealed that nonsense (38.2%) and frameshift (36.4%) variants were the predominant types. Intellectual disability/developmental delay was present in 100.0% of patients, epilepsy in 83.6%, and autism spectrum disorder in 41.3%. The incidence of epilepsy differed significantly among variant types (P = 0.045). Exons 8 and 15 were identified as mutation hotspots.
CONCLUSION
This study has identified a SYNGAP1 c.725G>A variant in the Chinese population and confirmed it as a potential cause of MRD5, which expanded the mutational spectrum of this disorder.
Humans
;
Female
;
Child, Preschool
;
Intellectual Disability/genetics*
;
ras GTPase-Activating Proteins/genetics*
;
Phenotype
;
Exome Sequencing
;
Genetic Association Studies
5.Analysis of ten cases of Acute lymphoblastic leukemia with non-KMT2A::AFF1 transcriptional variant 11q23 rearrangements.
Yuanyuan WANG ; Shuzhen FU ; Yong SHEN ; Qingxia XU
Chinese Journal of Medical Genetics 2026;43(4):265-272
OBJECTIVE:
To analyze the clinical characteristics of patients with 11q23 rearrangement acute lymphoblastic leukemia (ALL) with non-KMT2A::AFF1 fusion genes.
METHODS:
The clinical data of 10 patients with KMT2A fusion gene positive and partner gene non-AFF1 ALL admitted to Henan Cancer Hospital from December 2016 to December 2024 were retrospectively summarized. The immunophenotype, molecular genetic characteristics, clinical manifestations and disease prognosis of these patients were analyzed. This research has been approved by the Medical Ethics Committee of Henan Cancer Hospital (Ethics No.: 2019342).
RESULTS:
Among the 10 patients, the fusion genes were KMT2A::MLLT1 in 7 cases, KMT2A::MLLT4, KMT2A::MLLT3 and KMT2A::MLLT10 in 1 case each. The European Group for the Immunological Classification of Leukemias (EGIL) classification included 6 cases of T-ALL, 2 cases of pro-B-ALL, 1 case of Common-B-ALL and 1 case of pre-B-ALL. 4 cases of B-ALL all expressed CD19, cCD79a, CD38 and HLA-DR, and some expressed CD34 and CD22, without expression or weak expression of CD10, without expression of CD20. One case was accompanied by myeloid marker CD15 expression. 6 cases of T-ALL all expressed CD34, CD7, most expressed CD38, and some expressed CD3, CD5, CD2, CD4 and CD8, and 1 case expressed CD4 and CD8 together. Chromosomal abnormalities were detected in 3 cases, 5 cases were positive for WT1 fusion gene, and 6 cases had gene alterations. 9 patients achieved the first complete remission (CR1) during chemotherapy, and 1 patient relapsed within 6 months after CR1. At the last follow up, 1 patient (the fusion gene was KMT2A::MLLT4) remained unrelieved. There were 2 cases of KMT2A rearrangement (KMT2A-r) persistent positive (+/+) and 8 cases of KMT2A-r negative (+/-). The overall survival (OS) rate and leukemia-free survival (LFS) rate of patients with KMT2A-r persistent positive were significantly lower than those of patients with negative change, and the differences were statistically significant (P values were all < 0.05). Among the 3 patients who received chemotherapy+allogeneic hematopoietic stem cell transplantation (allo-HSCT), no relapse was observed until the follow up day. The OS rate and LFS rate of patients with KMT2A::MLLT1 and chemotherapy+allo-HSCT were higher than those of non-KMT2A::MLLT1 and single chemotherapy patients, and the differences were not statistically significant (P values were all ≥ 0.05). There was no significant difference in OS rate and LFS rate between T-ALL and B-ALL patients (P values were all ≥ 0.05). The median LFS time of the 10 patients was 32 (0 ~ 100) months, and the median OS time was 36 (1 ~ 101) months.
CONCLUSION
The 11q23 rearrangement ALL with non-KMT2A::AFF1 transcript is mainly KMT2A::MLLT1, T-ALL is more common, and the rate of chromosomal karyotype detection is relatively low. Persistent positive KMT2A-r is unfavorable for patient survival, and allo-HSCT during the CR1 period may improve patient survival.
Humans
;
Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics*
;
Female
;
Male
;
Myeloid-Lymphoid Leukemia Protein/genetics*
;
Histone-Lysine N-Methyltransferase/genetics*
;
Adult
;
Adolescent
;
Chromosomes, Human, Pair 11/genetics*
;
Child
;
Transcriptional Elongation Factors/genetics*
;
Gene Rearrangement
;
Oncogene Proteins, Fusion/genetics*
;
Retrospective Studies
;
Young Adult
;
Middle Aged
;
Prognosis
;
Child, Preschool
;
DNA-Binding Proteins/genetics*
6.Clinical analysis of a child with heterotopic ventricular gray matter Renpenning syndrome caused by PQBP1 gene mutation and a literature review.
Yazhen FAN ; Jianchuang ZHAO ; Qian CHEN ; Xianjie HUANG ; Fan LI ; Junying QIAO
Chinese Journal of Medical Genetics 2025;42(3):314-321
OBJECTIVE:
To explore the genetic etiology of a child with Renpenning syndrome (RS), and review the literature on the clinical characteristics and gene mutations of RS.
METHODS:
A child with RS (patient 1) who was diagnosed and treated in the Pediatric Intensive Care Unit of the Third Affiliated Hospital of Zhengzhou University in November 2023 was selected as the research object. The medical history, family history, physical examination, cerebrospinal fluid examination, echocardiography, brain magnetic resonance imaging (MRI), brain magnetic resonance angiography, cardiac coronary CT angiography and intelligence quotient (IQ) score of child 1 were retrospectively collected. Peripheral venous blood samples were collected from patient 1, his parents, sister and brother, respectively. Genomic DNA was extracted from the child and his family members, and Trios-whole exome sequencing (Trios-WES) was performed. Sanger sequencing was used to verify the pedigree. Bioinformatics softwares (Mutation Taster, REVEL, SIFT, PolyPhen-2, GERP++, SWISS-MODEL) were applied. The pathogenicity of the detected variants was rated according to the American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Classification of Genetic Variants (hereinafter referred to as the ACMG Guidelines). "PQBP1 gene" "Renpenning syndrome" "PQBP1 gene" "Renpenning syndrome" were used as keywords in Chinese and English, respectively. Case reports of patients with RS caused by PQBP1 gene variants were retrieved from Wanfang Data Knowledge Service Platform, China National Knowledge Infrastructure and PubMed database. The clinical features and gene variants of RS caused by PQBP1 gene variants were summarized and analyzed. This study was reviewed by the Medical Ethics Committee of the Third Affiliated Hospital of Zhengzhou University (Approval No. 2024-334-01).
RESULTS
The patient 1, a 12-year-old boy, was admitted to the hospital due to fever and disturbance of consciousness. Cerebrospinal fluid test showed viral encephalitis caused by human herpesvirus 7 infection. The main clinical manifestations were unusual facies (microcephaly, long narrow face, microphthalmos, superior oblique palpebral fissure, hypertelorism of inner canthus, bulbous nasal columella) and mental retardation. Auxiliary examination showed than patient 1 had atrial septal defect, nodular heterotopia in the posterior horn of the left ventricle, angiodysplasia, and low IQ. The disease began in infancy, and there was no family history of related diseases. A hemizygous deletion, c.459_462del (p.Arg153SerfsTer41), was identified in exon 5 of the PQBP1 gene in patient 1, which was inherited from his mother by Sanger sequencing. The results of bioinformatics analysis showed that the mutation was harmful. This variant was rated as pathogenic (PVS1+PS4+PM2_Supporting+PP3) according to ACMG Guidelines. According to the literature search strategy set in this study, a total of 13 cases of RS were retrieved, involving 16 cases of RS patient caused by PQBP1 gene mutation (patients 2-17), including patient 1, a total of 17 cases of RS. Among the 17 patients, 16 male patients had hemizygous mutations in the X chromosome PQBP1 gene, and 1 female patient had heterozygous mutations, including 12 deletion frameshift nonsense mutations, 3 point missense mutations, and 2 duplication mutations. Except for two fetuses, all patients had special facial features and low IQ to varying degrees. Ten patients had abnormal development of one or more organs such as eyes, heart, brain, etc. CONCLUSION: The main clinical manifestations of RS are developmental delay, long narrow face, bulbous nose, microcephaly, and may be accompanied by heterotopia of gray matter of ventricle and congenital heart disease. The c.459_462del (p.Arg153SerfsTer41) variant of the PQBP1 gene is the genetic basis of patient 1 in this study.
Humans
;
Male
;
Mutation
;
Pedigree
;
Child
;
DNA-Binding Proteins/genetics*
;
Nuclear Proteins/genetics*
;
Female
;
Exome Sequencing
7.Genetic analysis of a case of Miller-McKusick-Malvaux syndrome type 1 caused by CUL7 gene variant and a literature review.
Liming ZHANG ; Xue WU ; Jianwei YANG ; Hongqi SUN ; Junmei YANG ; Yongxing CHEN
Chinese Journal of Medical Genetics 2025;42(3):343-348
OBJECTIVE:
To explore the clinical features, genetic characteristics in a child with Miller-McKusick-Malvaux syndrome (3MS) type 1 caused by CUL7 gene variant.
METHODS:
A child diagnosed with 3MS type 1 at the Children's Hospital Affiliated to Zhengzhou University in February 2021 was selected as the subject of this study. Peripheral blood samples were collected from the child and her parents for genomic DNA extraction. Whole exome sequencing (WES) was performed on the child, and Sanger sequencing was used to validate the candidate variants and analyze their pathogenicity. A literature search was conducted using the keywords "3M syndrome" in the China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, and PubMed databases from inception to December 2024. The clinical data of Chinese children with 3MS reported in the literature were summarized. This study was approved by the Medical Ethics Committee of the Children's Hospital Affiliated to Zhengzhou University (Ethics No. 2024-K-020).
RESULTS:
The child was a 6-year-old and 2-month-old female with facial dysmorphism, skeletal abnormalities, and growth and developmental delay. WES revealed compound heterozygous variants in the CUL7 gene: c.2686G>T (p.E896*) and c.1200delT (p.R401Gfs66). Sanger sequencing confirmed that these two variants were inherited from the child's father and mother, respectively. According to the American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants, c.2686G>T (p.E896) was classified as a pathogenic (PVS1+PM2_Supporting+PM3), and c.1200delT (p.R401Gfs*66) was classified as a likely pathogenic (PVS1+PM2_Supporting). Based on the literature search strategy, 18 relevant articles were identified, including a total of 32 Chinese cases of 3MS, of which 8 were fetuses. A total of 32 Chinese 3MS cases were included in the literature review, of which 8 were fetuses. The majority of these cases carried variants in the CUL7 gene (20/32, 62.5%) and OBSL1 gene (12/32, 37.5%). The main clinical manifestations included intrauterine or postnatal growth and developmental delay (32/32, 100.0%), triangular facies (27/32, 84.3%), and skeletal abnormalities (21/32, 65.6%).
CONCLUSION
The compound heterozygous variants c.2686G>T (p.E896*) and c.1200delT (p.R401Gfs*66) in the CUL7 gene are likely the genetic cause of 3MS type 1 in the child. For children presenting with facial dysmorphism, skeletal abnormalities, and intrauterine or postnatal growth and developmental delay, 3MS should be considered as a differential diagnosis.
Humans
;
Cullin Proteins/genetics*
;
Female
;
Child
;
Limb Deformities, Congenital/genetics*
;
Exome Sequencing
;
Mutation
;
Child, Preschool
;
Dwarfism
;
Muscle Hypotonia
;
Spine/abnormalities*
8.Clinical and genetic characteristics of familial cases with Glucose transporter 1 deficiency syndrome.
Meijiao ZHANG ; Shimin ZHANG ; Qingping ZHANG ; Yongxin WEN ; Jiaping WANG ; Hui XIONG ; Yuwu JIANG ; Xinhua BAO
Chinese Journal of Medical Genetics 2025;42(4):424-432
OBJECTIVE:
To elucidate the clinical and genetic characteristics of familial cases with Glucose transporter type 1 deficiency syndrome (Glut1DS).
METHODS:
A survey of family history was conducted on children (proband) with Glut1DS who had visited Peking University First Hospital between November 2008 and April 2024 by focusing on the clinical manifestations of family members. Peripheral venous blood (2 mL) was collected from the pediatric patients and their parents. Genomic DNA was extracted and sequenced subsequently. Sanger sequencing was performed to validate the identified variant sites of the SLC2A1 gene in the probands and their family members. The pathogenicity of suspected variants was analyzed according to the 2015 American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants. The clinical features, auxiliary examinations, and mutational characteristics of family members with SLC2A1 variants were analyzed. This study has been approved by the Clinical Research Ethics Committee of Peking University First Hospital (Ethics No. 2021 Research 332).
RESULTS:
Among 87 cases with Glut1DS, 10 families with autosomal dominate inherited cases were identified, accounting for 11.0% of the cases. Of the 11 children, 8 were boys and 3 were girls. The onset of the disease had ranged from 3 months to 120 months (median 6 months), with 4 cases of early-onset classic type, 2 cases of late-onset classic type, and 5 cases of non-classic type. Six children had seizures, and 7 exhibited movement disorders. Seven children underwent developmental assessment, of which 3 had mild developmental delay, 2 were borderline, and 2 were normal. Nine children underwent lumbar puncture. The cerebrospinal fluid glucose levels ranged from 1.45 to 2.25 mmol/L (median 1.86 mmol/L), and the cerebrospinal fluid to blood glucose ratios ranged from 0.29 to 0.44 (median 0.35). Among the 8 fathers with SLC2A1 gene variants, 4 were asymptomatic, 2 developed paroxysmal exercise-induced movement disorders (PED) in childhood and adulthood, respectively. 1 had poor memory since childhood, 1 developed migraines during adolescence, and his sister was an asymptomatic carrier. The father with childhood-onset PED had a cerebrospinal fluid test with CSF glucose of 1.85 mmol/L. Of the 3 mothers with SLC2A1 gene mutations, 1 was an asymptomatic carrier; 2 developed PED in childhood and after the age of 20, respectively. The mother who developed PED in childhood also had psychomotor developmental delay. Genetic testing results revealed that among 10 families, 8 carried missense variants, 1 carried a nonsense variant, and 1 carried a small fragment insertion leading to a frameshift variant. Among the 11 cases, SLC2A1 gene variants in 8 children were inherited from their fathers, while in 3 cases, the variants were inherited from their mothers. The pathogenicity of the genetic variants was evaluated according to the Standards and Guidelines for the Interpretation of Sequence Variants published by the ACMG. Among the 8 variants identified in the 10 families, 4 were classified as pathogenic variants, 1 as likely pathogenic, and 3 as variants of uncertain significance (VUS). Four variant sites, including c.204_205insTCTC (p.V69fs), c.412G>C (p.G138R), c.431T>G (p.V144G), and c.875A>G (p.Y292C), were not previously reported in the literature. Among these, the latter three were categorized as VUS.
CONCLUSION
Familial Glut1DS account for 11.0% of the cases in China, with the majority of SLC2A1 gene variants inherited from the fathers, predominantly missense mutations, and with an autosomal dominant inheritance pattern. Probands tend to have earlier onset and more severe symptoms than their parents, who often present with mild or no symptoms.
Humans
;
Male
;
Female
;
Glucose Transporter Type 1/deficiency*
;
Monosaccharide Transport Proteins/deficiency*
;
Child
;
Child, Preschool
;
Carbohydrate Metabolism, Inborn Errors/genetics*
;
Mutation
;
Infant
;
Pedigree
;
Adolescent
;
Adult
9.Genetic analysis of six adult patients with Dilated cardiomyopathy and analysis of structural variants.
Xuesen LIU ; Yaoyu SONG ; Jing ZHANG ; Huafeng QIU ; Jingjing SANG ; Juan ZHANG
Chinese Journal of Medical Genetics 2025;42(4):433-440
OBJECTIVE:
To investigate the genetic etiology of six adult patients with Dilated cardiomyopathy (DCM), and analyze the structure of the identified variants, for providing reference for the diagnosis of DCM.
METHODS:
Six adult patients with DCM (patients 1-6) admitted to the Department of Cardiology of Zhumadian Central Hospital from January 2023 to December 2023 were recruited. Clinical data of the patients were retrospectively collected. And 5 mL of peripheral blood was collected from each patient. Pathogenic variants of the patients were detected by whole exome sequencing (WES), and candidate variants were verified by Sanger sequencing. The possible functional significance of the identified missense variants was evaluated using software including SIFT, PolyPhen-2 and Mutation Taster. Specific regions of the MYBPC protein encoded by the MYBPC3 gene from different species were aligned using Mutation Taster. The wild-type and mutant MYBPC proteins were constructed using homologous modeling software MODELLER v10.4 and three-dimensional structures were visualized using PyMOL software. The molecular interaction between MYBPC-C5 domain and myosin with or without the mutation was further analyzed using ZDOCK module in Discovery Studio 2019 software. Pathogenicity ratings for the detected variant sites were performed in accordance with the Standards and Guidelines for the Interpretation of Sequence variants by the American College of Medical Genetics and Genomics (ACMG) (hereafter referred to as the ACMG Guidelines). This study was reviewed and approved by the Ethics Committee of Zhumadian Central Hospital (Approval No. 2022092007).
RESULTS:
The six DCM patients had typical symptoms of heart failure, and echocardiography showed whole-heart dilation and decreased ventricular wall motion, left ventricular end-diastolic dimension (LVEDD) was 59-74 mm, left ventricular ejection fraction (LVEF) was 35%-43%, and left ventricular fractional shortening (LVFS) was 17%-28%. Variations of the DCM related genes, including a c.98473A>T (p.Lys32825*) variation of the TTN gene and a c.1976T>C (p.Ile659Thr) variation of the MYBPC3 gene, were identified in two patients. Multiple software predicted that both mutations were deleterious. MYBPC3-Ile659Thr mutation affected the highly conserved residue within the C5 domain of MYBPC. Three-dimensional structural analysis of homologous modeling revealed the alterations in amino acid properties and interactions with surrounding amino acids caused by the MYBPC3-Ile659Thr mutation. Further molecular docking analysis showed that the Ile659Thr mutation altered both the hydrogen bond and salt-bridge interactions between the MYBPC-C5 domain and the ligand myosin.
CONCLUSION
Two mutations associated with DCM were identified in this study. The abnormal conformation of the mutant protein further affected its interaction with the ligand myosin, resulting in the phenotype of DCM.
Humans
;
Cardiomyopathy, Dilated/genetics*
;
Male
;
Adult
;
Female
;
Carrier Proteins/chemistry*
;
Middle Aged
;
Mutation
;
Exome Sequencing
;
Mutation, Missense
;
Retrospective Studies
;
Myosin Binding Protein C
10.Genetic analysis for a pedigree with Structural heart defects and renal anomalies syndrome caused by variants of TMEM260 gene.
Lulu YAN ; Jinghui ZOU ; Juan CAO ; Jinxiang ZHANG ; Yuxin ZHANG ; Chunxiao HAN ; Yingwen LIU ; Haibo LI
Chinese Journal of Medical Genetics 2025;42(4):460-468
OBJECTIVE:
To explore the genetic characteristics of a fetus affected with Structural heart defects and renal anomalies syndrome (SHDRA).
METHODS:
A pedigree with SHDRA (fetus and the parents) who had visited the Affiliated Women and Children's Hospital of Ningbo University in April 2023 was selected as the study subject. Clinical data of the family were collected. A total of 10 mL of amniotic fluid cells from the fetus and 5 mL of peripheral blood samples from the parents were collected for genomic DNA extraction. Trio whole-exome sequencing (Trio-WES) was performed, and Sanger sequencing was used to validate candidate variants in the family. The identified variants were classified according to the Standards and Guidelines for the Interpretation of Sequence Variants established by the American College of Medical Genetics and Genomics (ACMG) (hereinafter referred to as the "ACMG Guidelines). Relevant research literature on SHDRA in domestic and international databases were searched for literature review. This study was approved by the Affiliated Women and Children's Hospital of Ningbo University (Ethics No. EC2023-094).
RESULTS:
In this family, prenatal ultrasound at 18 weeks of gestation revealed left renal multicystic dysplasia in the fetus. After birth, the infant exhibited an ostium secundum atrial septal defect, patent ductus arteriosus, and left renal multicystic dysplasia. Trio-WES revealed that the fetus had carried c.344dup (p.L116Afs*32) and c.90_104dup (p.Ala31_Ala35dup) compound heterozygous variants in the TMEM260 gene, which were respectively inherited from its father and mother. According to the ACMG guidelines, the c.344dup (p.L116Afs*32) and c.90_104dup (p.Ala31_Ala35dup) variants were classified as pathogenic (PM2_Supporting+PVS1+PP4) and likely pathogenic (PM2_Supporting+PM4+PM3+PP4), respectively. According to the literature search strategy set for this study, a total of 6 literature was retrieved, involving 25 SHDRA patients from 20 families. Together with the patients in this study, there were 14 TMEM260 gene variants, most of which were frameshift variants (7 types) and had located in exons 3, 11 and 13. The main clinical features of SHDRA were congenital heart malformation, renal abnormality and neurodevelopmental abnormality, and there was a lack of genotype-phenotype correlation.
CONCLUSION
The c.344dup (p.L116Afs*32) and c.90_104dup (p.Ala31_Ala35dup) variants of the TMEM260 gene probably underlay the SHDRA in this family. Above finding has provided a basis for clinical diagnosis and genetic counseling for the family.
Humans
;
Female
;
Pedigree
;
Membrane Proteins/genetics*
;
Male
;
Heart Defects, Congenital/genetics*
;
Kidney/abnormalities*
;
Pregnancy
;
Adult
;
Kidney Diseases/congenital*
;
Exome Sequencing
;
Mutation
;
Genetic Testing

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