1.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
2.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
3.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*
4.Clinical characteristics and genetic analysis of two children with Multiple mitochondrial dysfunction syndrome due to variants of IBA57 gene.
Qiuping WU ; Shan CHEN ; Lijuan LIU ; Xiangshu WEN ; Jingjing LI
Chinese Journal of Medical Genetics 2025;42(1):69-73
OBJECTIVE:
To investigate the clinical features and genetic variants associated with Multiple mitochondrial dysfunction syndrome (MMDS) type 3 in two children.
METHODS:
Two children diagnosed with MMDS type 3 at Zhuhai Maternal and Child Health Care Hospital in January 2021 were selected for this study. A retrospective analysis of their clinical data was carried out. Whole exome sequencing was conducted on the two children and their parents, followed by Sanger sequencing for candidate variants and bioinformatic analysis. Both children received comprehensive rehabilitative therapy and were followed up for 3 years. This study was approved by the Ethics Committee of Zhuhai Maternal and Child Health Hospital (Ethics No. 202380).
RESULTS:
The two MMDS type 3 children were monozygotic twin girls, aged 9 months, presenting with developmental regression, pyramidal signs, and other clinical manifestations. Cranial MRI revealed widespread abnormal signals and vacuolar changes in the white matter. Whole exome sequencing revealed that both children had harbored compound heterozygous variants of the IBA57 gene, namely c.286T>C (p.Tyr96His) and c.307C>T (p.Gln103Ter). Sanger sequencing confirmed that these variants were inherited from their father and mother, respectively. According to the American College of Medical Genetics and Genomics (ACMG) guidelines, both variants were classified as pathogenic (PM2_Supporting+PM3_Very Strong+PP3_Moderate; PVS1+PM2_Supporting+PM3). After treatment with vitamins, levocarnitine, ATP, coenzyme Q10, and other drugs, both children showed partial recovery of neurodevelopmental regression, with improvement in feeding and sleep. Over the 3-year follow-up, there was slow but progressive improvement in motor, language, and cognitive development.
CONCLUSION
The compound heterozygous variants c.286T>C (p.Tyr96His) and c.307C>T (p.Gln103Ter) of the IBA57 gene probably underlay the MMDS type 3 in the twin pair. Clinicians should be vigilant about the possibility of MMDS type 3 in children with neurodevelopmental regression and early cranial MRI findings indicating widespread white matter abnormalities with vacuolar changes, as these may be indicative of IBA57 gene variants.
Female
;
Humans
;
Infant
;
Calcium-Binding Proteins/genetics*
;
Exome Sequencing
;
Genetic Testing/methods*
;
Microfilament Proteins/genetics*
;
Mitochondrial Diseases/genetics*
;
Mutation
;
Retrospective Studies
;
Carrier Proteins
5.Clinical and genetic analysis of an individual with Lan-negative rare blood group due to variant of ABCB6 gene.
Xianguo XU ; Kairong MA ; Ying LIU ; Xiaozhen HONG ; Yanling YING ; Faming ZHU
Chinese Journal of Medical Genetics 2025;42(3):286-291
OBJECTIVE:
To investigate a case of antibodies against high-frequency erythrocyte antigens and elucidate the genetic mechanism underlying the blood group.
METHODS:
A Lan-negative patient referred to the Zhejiang Blood Center by Quzhou Hospital of Traditional Chinese Medicine in August 2016 was selected as the study subject. A retrospective study was conducted to collect the proband's clinical data. The proband's erythrocyte antigens and unexpected serum antibodies were identified using tube saline and microcolumn agglutination anti-human globulin methods. Antibody specificity was determined by treating erythrocytes with 7 enzymes and 2 chemical reducing agents. Genomic DNA was extracted from the proband's blood sample for whole genome sequencing (WGS) and erythrocyte blood group gene analysis, with validation by Sanger sequencing. Multiple bioinformatics tools were used to analyze the pathogenicity of the variant. The rare blood group and unexpected antibody specificity were comprehensively determined based on the results of serological and genetic testing. This study has been approved by the Zhejiang Provincial Blood Center Medical Ethics Committee(Ethics No.20190201).
RESULTS:
The proband was a 91-year-old Han Chinese male with prostatitis, cystitis, and malnutrition in conjunct with emaciation. He had a history of multiple erythrocyte transfusions without observable adverse reactions. Prior to the most recent transfusion, major crossmatch agglutination was observed, which prompted antibody identification. Antibodies against high-frequency antigens were detected in the proband's serum, with enzyme and reducing agent treatments ruling out antibody specificities associated with 17 blood group systems, e.g., MNS, LU, KEL. WGS analysis identified 4 525 SNPs and 1 046 INDEL variants among erythrocyte blood group genes. Further screening revealed that the proband had a rare blood group due to a homozygous rs755723161 variant. This variant in the ABCB6 gene (c.459delC) has led to a frameshifting mutation (p.Trp154GlyfsTer96), resulting in the Lan-negative rare blood group with a high-frequency antigen deficiency and the production of IgG anti-Lan antibodies in the serum.
CONCLUSION
This study has identified anti-Lan alloantibodies in a Lan-negative patient and, for the first time, elucidated the ABCB6 gene variant underlying the Lan-negative rare blood group in the Chinese population.
Humans
;
Male
;
Blood Group Antigens/immunology*
;
Aged, 80 and over
;
Retrospective Studies
;
ATP-Binding Cassette Transporters
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.A case of complex structural variants in the Xq28 region diagnosed by whole genome sequencing.
Yulai YANG ; Chuang LI ; Ming GAO ; Yuan LYU
Chinese Journal of Medical Genetics 2025;42(3):355-359
OBJECTIVE:
To re-analyze a likely pathogenic variant in the Xq28 region identified by copy number variation sequencing (CNV-seq) through whole genome sequencing (WGS).
METHODS:
A fetus found to harbor a duplication in the Xq28 region by CNV-seq at Shengjing Hospital Affiliated to China Medical University in May 2023 was selected as the study subject. WGS was carried out for the fetus and its parents. Bioinformatic software was used to analyze the chromosomal structure and CNVs. Quantitative PCR (qPCR) was applied to determine the expression level of the MECP2 gene. This study has been approved by the Ethics Committee of Shengjing Hospital (Ethic No. 2013PS33K).
RESULTS:
A duplication (ChrX:153302641_153503563) and four breakpoints were identified on the X chromosome of the fetus' father. Bioinformatic analysis revealed that the duplicated region has involved exons 1 to 3 and part of the 5'-UTR of the MECP2 gene, which was inserted into the Xp11 region. Additionally, an inversion was detected in the Xp11 region adjacent to the duplicated segment. RT-PCR results showed normal level of MECP2 mRNA expression. The Xq28 duplication has not encompassed the entire MECP2 gene, nor disrupted its structure or altered its expression.
CONCLUSION
WGS has enabled more precise diagnosis of chromosomal structural variants and provided guidance for accurate genetic counseling for the affected families.
Humans
;
Female
;
Chromosomes, Human, X/genetics*
;
DNA Copy Number Variations/genetics*
;
Whole Genome Sequencing/methods*
;
Methyl-CpG-Binding Protein 2/genetics*
;
Pregnancy
;
Male
;
Adult
8.Progress in research on syndromic deafness associated with variants of CREBBP gene.
Chinese Journal of Medical Genetics 2025;42(3):368-374
CREBBP gene encodes the transcriptional co-activator CREB-binding protein. This protein can participate in cell growth, differentiation and development through a variety of signal transduction pathways. Variants in this gene may cause syndromic deafness by affecting signal transduction pathways and development of skeletal and nervous systems. This review has summarized the structure and function of the CREBBP gene and the pathogenetic mechanism of syndromic deafness caused by CREBBP gene variants, with an aim to provide a basis for clinical diagnosis and treatment.
Humans
;
CREB-Binding Protein/chemistry*
;
Deafness/genetics*
;
Mutation
;
Animals
;
Syndrome
;
Signal Transduction
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.Clinical manifestations and genetic variation analysis in six Chinese pedigrees affected with Stargardt disease.
Lijuan ZHANG ; Tao MA ; Ruiqi ZHANG ; Ximei ZHANG
Chinese Journal of Medical Genetics 2025;42(5):547-555
OBJECTIVE:
To explore the correlation between clinical manifestations and genetic variations in six Chinese Stargardt disease pedigrees.
METHODS:
Six Stargardt disease pedigrees due to ABCA4 gene variants that visited Shanxi Eye Hospital from June 2021 June 2023 were selected as the study subjects. A retrospective study method was used to collect the clinical and family history data of all members of these pedigrees. Peripheral venous blood samples of the examinees were collected, and genomic DNA was extracted for trio-WES. Candidate variants of the ABCA4 gene were verified by family Sanger sequencing. According to the "Standards and Guidelines for the Classification of Sequence Variants" (hereinafter referred to as the "ACMG Guidelines") formulated by American College of Medical Genetics and Genomics (ACMG), the variant sites of the ABCA4 gene were classified for pathogenicity. This study has been approved by the Medical Ethics Committee of Shanxi Eye Hospital (Ethics No. SXYYLL-20200620).
RESULTS:
From June 2021 to June 2023, 7 patients (patient 1 to 7) from families with Stargardt disease with ABCA4 variants were selected as the study subjects. The age of the patients was between 7 to 53 years old, and the age of onset was between their 6 to 15 years old. All patients had exhibited moderate-to-severe visual impairment with macular atrophy, and yellow white spots were seen in all patients except patient II2 in family 5. Optical coherence tomography (OCT) results showed that all patients' macular fovea was significantly thinner, with IS/OS or ellipsoid zone disappeared. Autofluorescence showed low autofluorescence in the macula, and abnormalities dot autofluorescence in the paramacular and periphery retina. ERG grouping classified three pedigrees as Group 3, two as Group 1, and one as Group 2. Genetic analysis results showed that all pedigrees had autosomal recessive inheritance, five had compound heterozygous variants in the ABCA4, and one had homozygous variants. In total 11 pathogenic mutations were detected in the ABCA4 gene, of which 3 were found for the first time, including p.Glu1704Gly, p.Gly1965Glu and p.Ser1531Phe. Patients carrying nonsense or frameshift mutations include patient 1 (family 1, II1), patient 2 (family 1, II2), patient 4 (family 3, II1), patient 6 (family 5, II2), and patient 7 (family 6, II1), whose clinical manifestations are more severe than those of patient 3 (family 2, II2) and patient 5 (family 4, II1), whom carried missense mutations in terms of best corrected visual acuity (BCVA) damage.
CONCLUSION
The ABCA4 gene variations may be the genetic cause of the Stargardt disease in this study, and the discovery of the ABCA4 gene p.Glu1704Gly, p.Gly1965Glu, p.Ser1531Phe variants has enriched the mutational spectrum of Stargardt disease.
Adolescent
;
Adult
;
Child
;
Female
;
Humans
;
Male
;
Middle Aged
;
Young Adult
;
ATP-Binding Cassette Transporters/genetics*
;
China
;
Genetic Variation
;
Macular Degeneration/congenital*
;
Mutation
;
Pedigree
;
Retrospective Studies
;
Stargardt Disease/genetics*
;
East Asian People/genetics*

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