中华医学遗传学杂志最新文献

Objective: To explore the genetic variants and phenotypic characteristics of patients with Neurofibromatosis type I (NF1).

Methods: Twenty two NF1 patients who presented at Enze Medical (Center) Group in Taizhou between 2018 and 2024 were selected as the study subjects. Clinical phenotype and family history were collected for the patients. Whole exome sequencing (WES) was carried out for the 22 probands to screen the variants of NF1 gene. Candidate variants were verified by Sanger sequencing of their family members. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: K20230902).

Results: The 22 probands were diagnosed between the age of 5 months to 47 years old, and have all shown cafe au lait spots on their skin. Seventeen patients exhibited the phenotype at birth, and 11 had various degrees of neurofibromatosis. Among them, probands 1 and 13 underwent surgical resection of the tumor but had recurred, while proband 12 had amputation due to the huge size and serious impact of the neurofibroma and had no recurrence. Five patients had various degrees of scoliosis. In total 22 germline mutations and one somatic mutation were identified among the 22 families, with 5 variants unreported previously, including 1 nonsense mutation c.1603C>T (Q535*), 3 frameshift mutations [c.7268_7269delCA (Thr2423fs), c.2293del (Arg765Alafs*26), and c.5433_5438delinsGC (Phe1812ArgfsTer50)], and 1 deletion involving exons 41-44 of the NF1 gene and adjacent introns. Proband 13 was found to harbor germline mutation c.6796C>T (Gln2266Ter) and somatic mutation c.1019_1020del (Ser340Cysfs Ter12) in the peripheral blood and tumor tissue, respectively. Among the 22 NF1 probands, 6 had received treatment due to severe illness. Proband 1 had tumor resection in the right upper limb, but was found to have malignant lung tumor and died during follow-up. Proband 12 had multiple recurrence of neurofibroma in the left ring finger. Proband 4 underwent spinal correction surgery due to severe scoliosis. Proband 11 had died due to a central nervous system disease. Among the 22 germline mutations, 6 had led to the occurrence of truncated proteins, which may have a more severe impact on the phenotype.

Conclusion: This study investigated the genetic variants and clinical phenotypes of 22 NF1 families and identified 5 novel variants of the NF1 gene, which has expanded the genotypic and phenotypic spectra of the NF1. Preliminary studies have identified an association between truncated mutations, young age, and severe phenotypes, which may provide important clues for prognosis evaluation. For the clinical diagnosis and treatment of NF1, it is necessary to consider the phenotypic characteristics and genetic testing in combination with genetic counseling and long-term follow-up.

Objective: To explore the clinical phenotypes and genetic characteristics of five children with Lamb-Shaffer syndrome (LAMSHF).

Methods: Five children with LAMSHF diagnosed at the Department of Pediatrics, the First Medical Center of Chinese PLA General Hospital from April 2021 to December 2024 were selected as study subjects. Clinical data of the children was collected. Genomic DNA was extracted from peripheral blood samples of the children and their parents. Whole exome sequencing (WES) was carried out to screen for variants. This study was approved by the Medical Ethics Committee of the Chinese PLA General Hospital (Ethics No.: S2025-411-01).

Results: All five children had presented with global developmental delay. Among them, two had manifestations of autism spectrum disorder, two had abnormal electroencephalogram findings, four had abnormal MRI results, and two had ocular abnormalities. WES has detected five novel variants in the SOX5 gene. Among these, c.1771G>C (p.Gly591Arg) was unreported previously. Sanger sequencing confirmed that none of the parents had carried the same variants, suggesting that they were all de novo variants. According to the guidelines from the American College of Medical Genetics and Genomics (ACMG), two nonsense variants and one missense variant were classified as pathogenic, whilst two missense variants were classified as likely pathogenic.

Conclusion: This study has clarified the correlation between the clinical phenotypes of five children with LAMSHF and variants of the SOX5 gene, which expanded the mutational spectrum of the SOX5 gene and provided a basis for the clinical diagnosis and genetic counseling.

Objective: To investigate the genetic characteristics and clinical utility of Optical genome mapping (OGM) in resolving complex genomic rearrangements in families with recurrent pregnancy loss.

Methods: A recurrent miscarriage family which presented at both the People's Hospital of Qianxinan Buyi and Miao Autonomous Prefecture and the Affiliated Women and Children's Hospital of Ningbo University in September 2024 was selected as the study subject. Relevant clinical information was collected. Peripheral blood samples of the couple were collected for G banding karyotyping analysis, and copy number variation sequencing (CNV-seq) and OGM were used for verification. This study was approved by the Medical Ethics Committee of the Affiliated Women and Children's Hospital of Ningbo University (Ethics No.: EC2024-148).

Results: CNV-seq in an external hospital detected a 10.67 Mb deletion in the 16q12.1q21 region, a 142.4 kb deletion in the 5p15.2 region, and a 359.55 kb duplication in the 7p22.2 region. No abnormality was found in the chromosomal karyotype of the male partner, and the initial karyotyping of the female partner suggested 46,XX,?del(16)(q12.1q22). The CNV-seq verification of her indicated only variations in the 5p15.2 and 7p22.2 fragments, and no deletion of 16q was detected. As indicated by precise OGM analysis, multiple intrachromosomal and interchromosomal translocation variations had occurred between chromosomes 10 and 16 in the female partner, with complex balanced rearrangements (including 5 transchromosomal breakpoints).

Conclusion: The complex balanced rearrangements of the female partner's chromosomes had occurred during meiosis, the resultant unbalanced gametes may be the cause of repeated miscarriage in this family. OGM can delineate complex rearrangement breakpoints and directions that are difficult to reveal by conventional karyotyping analysis and provide a basis for accurate reproductive genetic counseling.

Objective: To investigate the clinical characteristics and genetic etiology of a Chinese pedigree affected with Hereditary dentin dysplasia type II (DD-II) due to variant of dentin sialophosphoprotein (DSPP) gene.

Methods: A child diagnosed with DD- II at the Third Clinical Division of Peking University Hospital of Stomatology in December 2021 and her family members were selected as study subjects. Clinical data were retrospectively analyzed. Saliva samples were collected from the proband, her parents and sister for genomic DNA extraction. Whole exome sequencing (WES) was carried out. Candidate variant was verified by Sanger sequencing and TOPO-TA cloning sequencing. The candidate variant was also subjected to bioinformatics analysis using Mutation Taster v2021. Secondary and tertiary structures of the wild-type and variant DSPP proteins were predicted with psipred v4.0 and PyMOL v2.3 software, respectively. The pathogenicity of the variant was classified based on the guidelines from American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of Peking University Hospital of Stomatology (Ethics No.: PKUSSIRB-202162021).

Results: The proband and her mother and sister had all exhibited typical clinical manifestations of hereditary DD-II. The primary dentition of the proband displayed yellowish brown discoloration, wear, and obliteration in the chamber and root canal, while the permanent teeth of the proband's sister and mother appeared nearly normal in both color and appearance, though with obliteration in the chamber and root canal. Her father showed normal dentition. WES identified a heterozygous c.1915_1918delAAGT, p.(Lys639Glnfs*674) frameshift variant in the DSPP gene. Sanger sequencing and TOPO-TA cloning sequencing confirmed the presence of this variant in the proband, the proband's sister, and the mother, while the proband's father was negative for the variant, indicating an autosomal dominant inheritance pattern. The variant was predicted to be pathogenic by Mutation Taster v2021. Prediction of the secondary structure of the DSPP protein showed that the variant has changed it from coil to helix. The tertiary structure prediction of the DSPP protein showed change of the spatial structure of the variant DSPP, with the loops in the variant region replaced by helices at multiple sites. Based on the guidelines from the ACMG, the variant was classified as pathogenic (PVS1+PM2_Supporting+PP1+PP4).

Conclusion: Phenotypic analysis and genetic testing of this family has clarified the clinical diagnosis of hereditary DD- II. The c.1915_1918delAAGT variant probably underlay the pathogenesis of DD-II in this family. Above results have expanded the phenotypic spectrum of the disease and may contribute to further clinical and genetic research on this disease.

Objective: To explore the genetic etiology of a Chinese pedigree affected with Primary ciliary dyskinesia (PCD).

Methods: A child who presented at the ENT Department of Zhengzhou University Children's Hospital in March 2024 due to secretory otitis media, chronic sinusitis, adenoid hypertrophy, dextrocardia, and bronchiectasis was selected as study subject. Relevant clinical data were collected. Peripheral blood samples from the child and her family members were collected. Following DNA extraction, whole exome sequencing was carried out. Candidate variants were validated by Sanger sequencing, and the correlation between the variants and phenotype was analyzed. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: 2024-K-135).

Results: The child and her elder siblings exhibited similar clinical manifestations including recurrent cough, secretory otitis media, chronic sinusitis, tracheobronchitis, and pneumonia. The child also presented with bronchiectasis and visceral situs inversus. Genetic testing results indicated that the child and her elder siblings had all harbored compound heterozygous variants of the DNAH11 gene, namely c.3000 1G>A and c.5775C>G (p.Tyr1925*), which were respectively inherited from their phenotypically normal parents. Both variants can affect mRNA splicing and protein translation integrity. Based on the guidelines from the American College of Medical Genetics and Genomics, both variants were classified as likely pathogenic. It was predicted that they may jointly lead to a functional defect in axonemal dynein, resulting in the phenotype of PCD, conforming to an autosomal recessive inheritance.

Conclusion: The compound heterozygous variants c.3000 1G>A and c.5775C>G (p.Tyr1925*) of the DNAH11 gene probably underlay the pathogenesis of PCD in this pedigree. The same variant in different individuals may lead to different clinical phenotypes, which has reflected significant heterogeneity in genetic background and clinical phenotype. Above findings have enriched the mutational spectrum of PCD gene and have important implications for the accurate diagnosis, treatment, prognosis, and genetic counseling.

Objective: To explore the prenatal features and genetic etiology of a fetus with Short-rib cage dysplasia (SRTD) due to variants of DYNC2H1 gene.

Methods: A pregnant women presented at Xinxiang Central Hospital in June 2020 for abnormal prenatal ultrasound findings was selected as the study subject. With informed consent obtained, amniotic fluid sample was extracted from the woman, and clinical data of the fetus were collected. Whole exome sequencing (WES) was carried out, and candidate variants were verified by Sanger sequencing. This study was approved by the Medical Ethics Committee of Xinxiang Central Hospital [Ethics No.: 2025-214-01(K)].

Results: At 25⁺⁶ weeks gestation, genetic testing revealed that the fetus has harbored compound heterozygous variants of the DYNC2H1 gene, namely c.10585C>T (p.Arg3529Ter) and c.8954T>G (p.Val2985Gly), which were derived from its father and mother, respectively. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.10585C>T (p.Arg3529Ter) and c.8954T>G (p.Val2985Gly) variants were classified as pathogenic (PVS1+PM2_supporting+PM3+PP5) and likely pathogenic (PM1+PM2_supporting+PM3+PP3), respectively. Bioinformatics analysis suggested that both variants may affect the 3D structure of the DYNC2H1 protein.

Conclusion: The compound heterozygous variants of c.10585C>T (p.Arg3529Ter) and c.8954T>G (p.Val2985Gly) of the DYNC2H1 gene probably underlay the pathogenesis of SRTD in the fetus. Above findings had facilitated prenatal diagnosis and genetic counseling for the couple.

Objective: To carry out pathological and genetic analyses on a fetus with intrauterine growth restriction and death during second trimester after induced abortion.

Methods: A fetus undergone induced abortion due to intrauterine growth restriction and death during second trimester at the the Seventh Affiliated Hospital of Sun Yat-Sen University in 2024 was selected as the study subject. Clinical data of the pregnancy were collected. DNA was extracted from tissues from the aborted fetus and peripheral blood samples from its parents. Chromosomal microarray analysis and whole exome sequencing were carried out. Candidate variants were verified by Sanger sequencing. Following abortion, routine autopsy and pathological analysis were conducted. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: KY-2025-334-01).

Results: The aborted fetus was a male and harbored compound heterozygous nonsense variants of the TH gene (c.457C>T/p.Arg153* and c.694C>T/p.Gln232*), for which both parents were heterozygous carriers. Autopsy and pathological analysis revealed that the fetus had pathological features including loose arrangement of myocardial fibers and congestion in the liver.

Conclusion: Biallelic null variants of the TH gene may cause heart failure by affecting the development of cardiovascular system, which in turn may lead to intrauterine death. This study has provided new clues for the molecular diagnosis of stillbirth and recurrent pregnancy loss.

Objective: To explore the genetic basis for a boy affected with Cohen syndrome.

Methods: A boy admitted to Children's Hospital of Nanjing Medical University in January 2021 was selected as the study subject. Genome DNA was extracted from peripheral blood samples from the child and his parents. Whole exome sequencing (WES) was carried out. And candidate variants were verified by Sanger sequencing. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: 202106060-1).

Results: WES revealed that the child has harbored compound heterozygous variants of the VPS13B gene, namely c.1563+1G>A and c.3007insC (p.A1003Afs*13), which were inherited from his mother and father, respectively. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were rates as pathogenic. The c.3007insC (p.A1003Afs*13) was unreported previously.

Conclusion: The compound heterozygous variants c.1563+1G>A and c.3007insC (p.A1003Afs*13) of the VPS13B gene probably underlay the pathogenesis of Cohen syndrome in this child. Above finding has enriched the mutational spectrum of VPS13B gene.

Objective: To explore the genetic etiology of a Chinese boy affected with Oculo-facio-cardio-dental syndrome (OFCD).

Methods: A child diagnosed with OFCD at West China Hospital of Sichuan University on September 21, 2024 was selected as the study subject. Clinical phenotype of the child was collected through ophthalmologic examination, cardiac ultrasonography, and X-ray imaging. Potential pathogenic variants were detected by trio-whole exome sequencing (Trio-WES). Candidate variant was validated with TA-cloning followed by Sanger sequencing. Mosaic variant was analyzed by ultra-deep sequencing (10,000-fold) and quantitative PCR. This study was approved by the Medical Ethics Committee of the West China Hospital of Sichuan University (Ethics No.: 2019-772 ).

Results: The proband had presented with congenital cataracts, mitosis, atrial and ventricular septal defects, dental abnormalities, and right radioulnar synostosis. His mother also exhibited congenital cataracts and dental anomalies, suggesting a diagnosis of OFCD. Trio-WES revealed an novel heterozygous 14-bp deletion (c.4724_4737del) in exon 12 of the BCOR gene in the proband. Deep sequencing identified a mosaic BCOR c.4724_4737del mutation in approximately 3.4% of peripheral leukocytes from his mother. Quantitative PCR analysis also confirmed the presence of this low-level mosaicism. The 14-bp deletion was predicted to cause a frame shift and premature termination (p.Met1575AsnfsTer6). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PVS1+PM2+PP1).

Conclusion: Above findings have expanded the spectrum of BCOR mutations associated with OFCD, which highlighted the role of low-level mosaicism with maternal transmission and provided a basis for genetic counseling and reproductive guidance for the family.

Objective: To explore the clinical features and genetic etiology in a child with Hereditary hemorrhagic telangiectasia (HHT) complicated by growth hormone deficiency.

Methods: A child presented at Yantai Yuhuangding Hospital in October 2014 for "short stature for over 4 years" was selected as the study subject. Peripheral venous blood samples were collected from the child and his parents for genomic DNA extraction and whole-exome sequencing (WES). The pathogenicity of the candidate variants was assessed by following 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.: 2025-003).

Results: The patient, a 4-year-and-2-month-old male, presented with short stature and recurrent epistaxis since early childhood. Initial diagnosis of GHD was made via growth hormone stimulation testing. During follow-up, telangiectatic macules and polycythemia gradually appeared. WES revealed that he has harbored a heterozygous c.1807G>A (p.Gly603Arg) variant of the ENG gene, which was absent in both parents and classified as likely pathogenic based on ACMG guidelines. Sanger sequencing confirmed the candidate variant to be de novo.

Conclusion: Patients with HHT combined with GHD may exhibit clinical features such as short stature, telangiectasia, and arteriovenous malformations. The heterozygous c.1807G>A (p.Gly603Arg) variant of the ENG gene probably underlay the pathogenesis of the disease in the proband. Above finding has expanded the mutational spectrum of the ENG gene.