中华医学遗传学杂志最新文献

Objective: To analyze the clinical characteristics of a patient with Short rib-polydactyly syndrome type 6 (SRTD6) with long-term misdiagnosis, and improve its clinical recognition by reviewing the relevant literature.

Methods: A patient presented at the Children's Hospital Affiliated to Zhejiang University School of Medicine on August 19, 2024 for the discovery of liver dysfunction for 13 years and vision loss for 9 years was selected as the study subject. Her medical history, clinical data, laboratory findings and results of imaging examination were collected. High-throughput sequencing was carried out, and candidate variants were verified by Sanger sequencing. This study was approved by the Ethics Committee of the Hospital (Ethics No.: 2021-IRB-292).

Results: The patient had long-term unexplained liver dysfunction, vision loss, and growth delay. Blood acylcarnitine and urinary organic acid analysis have failed to found any abnormality. Previous genetic testing revealed a homozygous c.203A>C (p.Glu68Ala) missense variant in the ETFDH gene, leading to a misdiagnosis of various acyl-CoA dehydrogenase deficiencies. However, treatment with high-dose vitamin B₂ showed a poor effect. Physical examination revealed small hands, short and stubby fingers, and a narrow chest. Medical imaging showed shortened bilateral ribs, a narrowed chest, and short, thick metacarpals. High-throughput sequencing has detected a pathogenic homozygous c.1957C>T (p.R653*) nonsense variant in the NEK1 gene, confirming the diagnosis of SRTD6.

Conclusion: SRTD6 is characterized by rib and sternum dysplasia as the primary skeletal deformities, which is often accompanied by multi-organ impairment. Genetic testing can facilitate the precise diagnosis.

Objective: To explore the clinical characteristics and genetic factors in four patients with Disorder of sex development (DSD).

Methods: Four patients who visited Tianjin Medical University General Hospital between January 2023 and January 2024, presenting with short stature, abnormal external genitalia, or infertility as their chief complaints, were selected as the study subjects. Clinical data were collected, and peripheral or umbilical cord blood samples were obtained for karyotyping analysis and low-depth whole-genome sequencing (CNV-seq). Quantitative fluorescence PCR (QF-PCR) was used to detect the sex-determining region Y (SRY) gene and azoospermia factor (AZF) on the Y chromosome, while fluorescence in situ hybridization (FISH) was employed to determine the location of the SRY gene. Whole exome sequencing (WES) was performed for genetic testing, and Sanger sequencing was used for familial validation of the candidate variants. The study procedure and protocol were approved by the Medical Ethics Committee of Tianjin Medical University General Hospital (Ethics No.: IRB2024-WZ-006).

Results: Case 1 had a karyotype of 45,X[22]/46,XY[8], with CNV-seq indicating a mosaic deletion of 7.44 Mb (copy number = 0.2) at Yp11.31-p11.2, a mosaic deletion of 5.32 Mb (copy number = 0.3) at Yq11.1-q11.221, and a deletion of 10.26 Mb (copy number = 0) at Yq11.221-q11.23. Y chromosome microdeletion analysis showed SRY and AZFa (+), AZFb+c (-). Case 2 had a karyotype of 45,X[12]/46,X,del(X)(q26.3)[18], with CNV-seq indicating a mosaic deletion of 132.62 Mb (copy number = 1.4) at Xp22.33-q26.3 and a deletion of 19.62 Mb (copy number = 1) at Xq26.3-q28. Case 3 had a karyotype of 46,XX, with CNV-seq showing two copies of the X chromosome and no Y chromosome. Y chromosome microdeletion analysis showed SRY (+) and AZFa+b+c (-), and FISH confirmed a translocation of the SRY gene to the terminal end of the short arm of the X chromosome. Case 4 had a karyotype of 46,XY, with CNV-seq showing one copy each of the X and Y chromosomes. Y chromosome microdeletion analysis showed SRY(+) and AZFa+b+c (+), and WES revealed a c.1103del variant in the AR gene (maternal origin), which was classified as a pathogenic variant based on the guidelines from the American College of Medical Genetics and Genomics (ACMG) (PVS1+PP1+PM2_Supporting).

Conclusion: The combined application of multiple detection techniques such as chromosomal karyotyping analysis, CNV-seq, QF-PCR, and WES can identify the genetic etiology of DSD patients, providing a basis for clinical consultation and treatment plan formulation.

Objective: To explore the genetic etiology for a child presenting with motor retardation, language delay, intellectual disability, and dysmorphic features.

Methods: A child presented at Linyi People's Hospital in June 2022 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples were obtained from the child and her parents. Following extraction of genomic DNA, whole-exome sequencing (WES) was carried out. Candidate variant was validated by Sanger sequencing. Amniotic fluid samples were obtained from the mother's subsequent pregnancies for prenatal diagnosis. This study has been reviewed and approved by the Medical Ethics Committee of Linyi People's Hospital (Ethics No.: 2019-134).

Results: The proband was a 2-year-old girl showing developmental delays in motor, language, and intellectual domains, strabismus, hypertelorism, hearing impairment, obesity, and brachymesophalangy of the fifth finger. Magnetic resonance imaging revealed abnormalities of the white matter. Chromosomal microarray analysis (CMA) identified a 15q26.3 duplication (chr15:101562020_102060896 × 3) inherited from her mother. WES has uncovered a heterozygous c.1931A>G (p.Tyr644Cys) variant in the FBXO11 gene. Sanger sequencing confirmed the variant to be de novo in origin. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as likely pathogenic. Prenatal diagnosis revealed that the fetuses from the mother's second and third pregnancies did not harbor the same variant.

Conclusion: The c.1931A>G (p.Tyr644Cys) variant of the FBXO11 gene probably underlay the abnormal phenotype in the child. Based on its genotype and phenotype, the proband was diagnosed with Intellectual developmental disorder with dysmorphic facies and behavioral abnormalities.

Objective: To explore the impact of age on the genetic variant spectrum and prognosis of patients with previously untreated Diffuse large B-cell lymphoma (DLBCL).

Methods: A retrospective analysis was conducted on the clinical data and follow-up information of 254 previously untreated DLBCL patients from 14 hospitals in the Jiangsu Cooperative Lymphoma Group (JCLG) enrolled from July 2018 and July 2023. Following extraction of DNA from tumor tissue samples, next-generation sequencing (NGS) technique was employed to analyze the genetic variant spectrum of the DLBCL patients, with an evaluation of the relationship between age and genetic variants as well as prognosis. This study was approved by the Medical Ethics Committee of the Affiliated Hospital of Nantong University (Ethics No.: 2023-K048-01).

Results: The median age of the 254 DLBCL patients was 62 years old, with 55% of patients aged 60 years or above. Clinical evaluation showed that younger (< 60 years) patients had higher complete response (CR) (70% vs. 59%), and objective response rate (ORR) (88% vs. 79%) than older patients, though the difference between the two groups was not statistically. Survival analysis indicated that both the five-year overall survival (OS) (82.7% vs. 71.7%, P = 0.006) and progression-free survival (PFS) (70.6% vs. 50.2%, P < 0.05) rates were significantly higher in younger patients. NGS showed that 99.6% of the patients harbored genetic variants, with PIM1, KMT2D, TP53, MYD88, and CD79B being the most common genes. Age significantly affected the variant frequency of certain genes, with MYC variants serving an adverse prognostic factor for OS in younger patients (P = 0.002), while TP53 (P = 0.024) and BCL2 (P = 0.002) variants significantly impacted OS in older patients. Prognostic analysis identified age ≥ 60 years (HR = 3.439, 95%CI: 1.318~9.874), presence of B symptoms (HR = 2.871, 95%CI = 1.133~7.307), and elevated lactate dehydrogenase (HR = 3.528, 95%CI = 1.231~10.66) as independent adverse prognostic factors.

Conclusion: Age, genetic variants, and clinical factors may significantly affect the prognosis of the DLBCL patients. Younger patients have better survival compared to older patients. Variants of the MYC, BCL2, and TP53 genes are closely associated with poor prognosis.

Objective: To explore the phenotypic and genotypic characteristics of a Chinese pedigree affected with Hereditary coagulation factor XI (FXI) deficiency.

Methods: A female patient with FXI deficiency and her family members (five individuals from three generations) who presented at Quanzhou First Hospital Affiliated to Fujian Medical University on September 19, 2024 due to diarrhea and fever were selected as study subjects. A retrospective study was conducted to collect the patients' clinical data. Peripheral venous blood samples were collected from the patient and her family members. Genomic DNA was extracted, followed by sequencing of all exons and flanking sequences of the F11 gene. Candidate variants were validated by Sanger sequencing of the family members, and their pathogenicity was classified according to the guidelines of the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of Quanzhou First Hospital [Approval No.: Quanyi Lun (2024) K281].

Results: The patient exhibited significantly prolonged activated partial thromboplastin time (APTT) of 80.9 seconds, while FXI activity (FXI:C) and FXI antigen (FXI:Ag) levels were extremely low (2% and 3%, respectively). Genetic analysis revealed that the proband harbored homozygous c.896C>G (p.Thr299Ser) missense variant in exon 9 of the F11 gene, for which her son was heterozygous. The variant was located in a highly conserved domain. Although Mutation Taster predicted it as a polymorphism, SIFT, PolyPhen-2, and LRT analyses suggested it to be likely pathogenic. Protein modeling indicated that the p.Thr299Ser variant may alter the hydrogen bonds between amino acids, thereby affecting the structure and function of the FXI protein. According to the ACMG guidelines, c.896C>G was rated as a likely pathogenic variant (PM1+PM2_Supporting+PP1_Strong+PP3+PP4).

Conclusion: The c.896C>G (p.Thr299Ser) missense variant of the F11 gene probably underlay the FXI deficiency in this pedigree. Above finding has enriched the mutational spectrum of the F11 gene and provided a basis for genetic counseling and prenatal diagnosis for this family.

Objective: To evaluate the differential expression of RNA in blood monocytes in patients with Juvenile idiopathic arthritis (JIA) treated with TNF antagonists (TNFi), and to explore the effect and mechanism of gene expression on the efficacy of JIA.

Methods: A total of 29 children with JIA treated with methotrexate (MTX) and TNFi in Guangzhou Women and Children's Medical Center of Guangzhou Medical University from April 2021 to November 2023 were enrolled. After 6 months, the children were divided into two groups according to the treatment effect, i.e., 13 cases in the ineffective group and 16 cases in the effective group, the peripheral blood of the children was collected, the blood mononuclear cells were isolated for transcriptome sequencing, the differentially expressed genes between the groups were analyzed, the signaling pathways and metabolic pathways related to the efficacy of TNFi were analyzed by GO and KEGG enrichment, and the mechanism related to the efficacy of TNFi was explored. This study was approved by Medical Ethics Committee of the Guangzhou Women and Children's Medical Center of Guangzhou Medical University (Ethics No.: 2023-330B00).

Results: There was a statistically significant difference in the gender and age distribution between the two groups of children (P < 0.05), while no statistically significant differences were observed in disease duration, rheumatoid antibody levels, or JIA subtypes (P > 0.05). After sequencing data quality control and comparison of reference genomes, a total of 18 523 protein-coding genes were identified in all children's samples. A total of 705 differentially expressed genes (DEGs) were identified between the effective group and the invalid group through differential analysis, of which 579 were up-regulated in the effective group and 126 in the inactive group. GO function and KEGG pathway enrichment analysis showed that DEG was significantly enriched in 55 GO entries and 32 KEGG metabolic pathways, which were mainly related to IL-1β production and regulation, cytokine production and regulation, cytokine-cytokine receptor interaction, immune response regulation, and Toll-like receptor signaling pathway.

Conclusion: DEG between the effective and ineffective groups of TNFi treatment may be involved in the biological processes such as cytokine production and regulation, cytokine-receptor interaction, and immune response regulation, which will be helpful to predict the efficacy and prognosis of TNFi treatment for JIA.

Objective: To explore the clinical and genetic characteristics of fetuses with Kabuki syndrome (KS) and their genotype-phenotype correlation.

Methods: A retrospective analysis was carried out on the prenatal manifestations and results of genetic testing of six KS fetuses diagnosed by whole-exome sequencing (WES). The findings were compared with 28 prenatally diagnosed KS cases reported in the literature to summarize the prenatal features of KS. This study has been approved by the Ethics Committee of Maternal and Child Health Care Hospital of Hubei Province (Ethics No.: 2025-141-01).

Results: Prenatal ultrasound findings in KS fetuses showed high heterogeneity. The most common abnormalities were cardiac (23/35, 65.7%) and renal (20/35, 57.1%), which are often accompanied by amniotic fluid abnormalities (5/35, 14.3%), single umbilical artery (5/35, 14.3%), and fetal hydrops (4/35, 11.4%). Among the six fetuses from our center, all were identified by WES to harbor pathogenic variants of the KMT2D gene, and all of which were de novo. These included 3 frameshift variants, 2 nonsense variant, and 1 missense variant, among which 4 were unreported previously.

Conclusion: This study has expanded the mutational spectrum of the KMT2D gene. Prenatal ultrasound findings of KS lack specificity, though multi-system anomalies or specific soft markers may indicate KS. WES is an effective tool for the diagnosis, and KS should be included in the differential diagnosis list for prenatal cardiac and renal abnormalities.

Objective: To explore the molecular mechanism of a case with RhD-- phenotype.

Methods: A proband with RhD-- phenotype who attended the clinic of the First Affiliated Hospital of Zhengzhou University on January 29, 2024 was selected as the study subject. Peripheral blood samples were collected from the proband (8 mL) and her close relatives (father, mother and brother; 3 mL each) for Rh phenotyping and irregular antibodies testing with gel card and test tube methods. Direct agglutination reaction and absorption-elution test were used to detect the c antigen on the red blood cells of the proband. PCR-sequence specific primers (PCR-SSP) typing and gene sequencing were used to determine the RHCE gene of the proband and her relatives. The origin of the proband's variant was traced by pedigree analysis. Three-dimensional structural models of the wild-type RhCE*cE protein and the RhD-- phenotype protein were constructed to predict the alterations of the RhD-- phenotype protein caused by the variant. The procedures of this study were approved by the Medical Ethics Committee of the First Affiliated Hospital of Zhengzhou University (Ethics No.: 2023-KY-0870-003).

Results: The red blood cells of the proband did not agglutinate with anti-C, anti-c, anti-E, and anti-e. The result of the serum irregular antibody test was negative. The results of direct agglutination reaction and absorption-elution test of the proband were both negative. Her Rh blood group was identified as RhD--. The results of the Rh blood grouping of her close relatives were normal. PCR-SSP detection showed that the RHCE genotypes of the proband and her close relatives were cE/cE and Ce/cE, respectively. Gene sequencing analysis showed that the RHCE genotypes of the proband and her close relatives were RHCE*cE (c.365C>A)/RHCE*cE (c.365C>A) and RHCE*Ce/RHCE*cE (c.365C>A), respectively. Pedigree analysis revealed that the variants in the proband were inherited from her father and mother, respectively. Homology modeling of RhCE*cE protein showed that the RhD-- type peptide chain with a significantly shortened C-terminal was encoded by only 121 amino acid resides, which was 296 amino acid resides shorter compared to the wild-type RhCE*cE peptide chain encoded by 417 amino acid residues.

Conclusion: Above results revealed the molecular biological mechanism of a RhD-- phenotype. The c.365C>A variant in the RHCE gene has rendered the RHCE*cE alleles invalid, which ultimately led to the RhD-- phenotype.

Objective: To investigate the clinical characteristics and genetic etiology of a child with Cortical dysplasia, complex, with other brain malformations 4 (CDCBM4) and epilepsy due to a TUBG1 gene variant.

Methods: A child diagnosed with CDCBM4 and epilepsy at the Children's Medical Center of the Affiliated Hospital of Guangdong Medical University in May 2024 was selected as the study subject. Clinical data were retrospectively analyzed. Peripheral venous blood samples were collected from the child and her parents for genomic DNA extraction. Trio-based whole-exome sequencing (WES) was performed, and candidate variants were validated by Sanger sequencing. According to the Standards and Guidelines for the Interpretation of Sequence Variants established by the American College of Medical Genetics and Genomics (ACMG), candidate variants were classified for pathogenicity. This study was approved by the Medical Ethics Committee of the Affiliated Hospital of Guangdong Medical University (Ethics No.: PJ2021-097).

Results: The child, a 4-month-old female infant, had no special facial features, normal limb muscle strength, and increased muscle tone of infantile onset, with generalized tonic-clonic seizures as the main manifestation. During seizures, she exhibited head retroflexion, tightly closed eyes, and tonic convulsions of the limbs, occurring approximately 2-3 times per day. Electroencephalogram suggested bilateral anterior predominant medium-to-high amplitude 7-8 Hz mixed rhythm discharges. Head MRI revealed ventricular system dilatation and pachygyria. Trio-WES results indicated that the child has harbored a TUBG1 gene variant of c.776C>T (p.Ser259Leu). Sanger sequencing verification showed that neither of her parents had carried the same variant, confirming it as de novo in origin. According to the ACMG guidelines, the variant was rated as pathogenic (PS2+PS3+PM2_Supporting+PP3). Combining the child's clinical phenotype, the child was diagnosed as CDCBM4 with epilepsy.

Conclusion: Children with CDCBM4 and epilepsy due to TUBG1 gene variants may show pachygyria or agyria and commonly present with intellectual and motor developmental delays and seizure disorders of variable severity. The heterozygous TUBG1 c.776C>T (p.Ser259Leu) variant is likely the genetic etiology underlying this disorder. The results of this study has expanded the mutational spectrum of the TUBG1 gene associated with CDCBM4 and epilepsy.