OBJECTIVE: To investigate the genetic mechanism for adverse pregnancies due to submicroscopic chromosomal structural variants in two cases, and to provide a precise guidance for preimplantation genetic testing. METHODS: Two families who had visited Chengdu Women's and Children's Central Hospital for reproduction guidance due to recurrent miscarriages, adverse pregnancy history and abnormal genetic testing of the offspring in June and December 2023 were selected as the study subjects. Chromosomal karyotyping and optical genome mapping (OGM) were carried out on peripheral blood samples from the two couples, and preimplantation genetic testing for structural rearrangement (PGT-SR) were performed on the blastocyst trophoblasts. This study was approved by the Medical Ethics Committee of the Hospital (Ethic No.: 2023-23). RESULTS: No abnormality was found on the G-banded karyotyping analysis for both couples. The OGM results revealed that the female partner of couple 1 had a translocation between 4pter-p16.3 (3.99 Mb) and 11pter-p15.4 (2.66 Mb), whilst no abnormality was found in the male partner. Similarly, the male partner of couple 2 had a translocation between 19q13.43-qter (1.90 Mb) and 22q13.31-qter (3.34 Mb). No abnormality was found in the female partner of couple 2. Neither breakpoints nor the adjacent region had involved an OMIM gene, except the formation of a fusion gene ZIM2-AS1-Z82186.1 (Both genes are non-coding, and the fusion gene was deemed as variant of unknown significance). PGT-SR of 11 blastocysts derived from couple 1 revealed that one embryo was suitable for priority transfer, three embryos were suitable for transfer, one embryo was recommended for genetic counselling, and six embryos were unsuitable for the transfer. For couple 2, six blastocysts were tested, of which only one embryo was deemed suitable for transfer. CONCLUSION When genetic testing of offspring indicates copy number variations such as deletions, duplications or mosaicism, the high-resolution OGM technique can be selected to screen parents for submicroscopic chromosomal structural variations. The result can facilitate accurate assessment for the risk of recurrence in offspring, selection of suitable method for reproduction, and identifying targets for PGT.
Humans ; Female ; Pregnancy ; Adult ; Male ; Karyotyping ; Chromosome Aberrations ; Abortion, Habitual/genetics* ; Preimplantation Diagnosis ; Genetic Testing

OBJECTIVE: To investigate the current status of clinical genetics specialization development and the diagnostic and therapeutic capabilities for hereditary diseases across medical institutions in Shanghai, and to assess the necessity and feasibility of establishing training bases for clinical genetics specialists. METHODS: By employing a cross-sectional survey design, the Clinical Genetics Committee of Shanghai Medical Association has conducted questionnaire surveys from March to April 2025 across 54 healthcare institutions in Shanghai (including 33 tertiary hospitals and 21 secondary hospitals). The survey involved administrative departments and medical personnel from 15 clinical specialties. The survey has covered current genetic disease diagnosis and treatment practices, relevant and specialised disease types, genetic department establishment, testing capabilities, personnel teams, and training requirements. RESULTS: The results revealed that 78.0% of clinical departments surveyed had treated patients with hereditary disorders. Shanghai possesses diagnostic and therapeutic expertise for over 95% of hereditary diseases listed in its rare disease catalogue, reflecting both the practical clinical demand for such conditions and the city's overall diagnostic and therapeutic strengths in this field. Nevertheless, significant disparities exist in the development of genetics departments across different tiers of healthcare institutions. Resources for genetic testing capabilities (including molecular, cellular, and biochemical testing) are also unevenly distributed across different tiers of hospitals. The survey further revealed that only 26.0% of departments believe that their current physician structure fully meets the diagnostic and treatment demands. Over 90% of departments consider standard training for clinical genetic specialists necessary, with 74.0% expressing willingness to participate in establishing training bases. Based on above findings and thorough deliberation, the Clinical Genetics Committee of the Shanghai Medical Association proposes advancing specialist training and discipline development through establishing a standard training system. The committee has drafted a three-year training protocol featuring a "joint training"-centered model, recommending a pilot-first, dynamically optimized strategy for steadily advancing training base development. CONCLUSION Shanghai faces substantial demand for genetic disease diagnosis and treatment, yet exhibits shortcomings in clinical genetics specialization development, resource allocation, and talent pipeline cultivation. To establish a standard training system holds significant practical importance and is underpinned by a broad demand.
Humans ; China ; Surveys and Questionnaires ; Genetic Diseases, Inborn/genetics* ; Cross-Sectional Studies ; Genetics, Medical/education* ; Genetic Testing

OBJECTIVE: To explore the genetic etiology of 46 Chinese pedigrees affected with Hereditary multiple exostoses (HME) and provide genetic counseling and reproductive intervention. METHODS: Whole-exome sequencing and Sanger sequencing were carried out on 87 patients from the 46 pedigrees to analyze the variants of EXT1 and EXT2 genes. Pathogenicity of the variants was assessed based on the guidelines from the American College of Medical Genetics and Genomics and Association for Molecular Pathology (ACMG/AMP). Prenatal diagnosis and preimplantation genetic testing (PGT) were provided for couples with identified pathogenic mutations. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: LL-SC-SG-2014-010). RESULTS: In total 17 and 22 pathogenic variants were respectively identified in the EXT1 and EXT2 genes, among which 5 EXT1 and 12 EXT2 variants were unreported previously. Three patients with no family history were found to harbor de novo variants of the EXT1 gene. Twenty nine couples had opted for PGT or underwent prenatal diagnosis following natural conception, and 17 healthy babies were born. CONCLUSION This study has clarified the genetic etiology of 45 HME pedigrees and identified 17 novel variants, which has enriched the mutational spectrum of the EXT1 and EXT2 genes. Reproductive intervention through PGT and prenatal diagnosis have prevented the recurrence of HME in these families.
Humans ; Female ; Male ; Pedigree ; Exostoses, Multiple Hereditary/diagnosis* ; N-Acetylglucosaminyltransferases/genetics* ; Adult ; Exostosin 1 ; Asian People/genetics* ; Genetic Testing ; Exostosin 2 ; Mutation ; China ; Prenatal Diagnosis ; Pregnancy ; Genetic Counseling ; Preimplantation Diagnosis ; Exome Sequencing ; East Asian People

OBJECTIVE: To explore the efficacy of a Thalassemia risk assessment software for the screening of thalassemia mutation carriers and distribution of thalassemia genotypes detected by screening. METHODS: A total of 6 040 individuals were evaluated at Leshan Maternal and Child Health Care Hospital between 2022 and 2024 using the commonly used clinical thalassemia risk assessment method and the thalassemia screening software, respectively, and the performance indicators of the two methods were compared and analyzed against the result of thalassemia gene testing. This study was approved by the Ethics Committee of our hospital (Ethics No.: LfyLL[2022]005). RESULTS: The high-risk rate by the thalassemia screening software was 11.19%, with a sensitivity of 95.12%, specificity of 93.28%, positive predictive value of 43.20%, negative predictive value of 99.72%, and the area under the ROC curve (AUC) was 0.942. The thalassemia gene detection rate of the high-risk samples screened was 4.83%. The high-risk screening rate of the conventional method was 2.50%, with a sensitivity of 51.22%, specificity of 93.28%, positive predictive value of 80.79%, negative predictive value of 97.40%, and the AUC was 0.754. The thalassemia gene detection rate of the high-risk samples was 2.02%. CONCLUSION The software can effectively detect thalassemia carriers and significantly reduce the missed detection compared with conventional method, thereby significantly improve the efficacy of screening.
Humans ; Thalassemia/diagnosis* ; Software ; Female ; Genetic Testing/methods* ; Male ; Mutation ; Adult ; Genotype ; ROC Curve ; Risk Assessment

OBJECTIVE: To assess the feasibility of first polar body transfer (PB1T) combined with preimplantation mitochondrial genetic testing for blocking the transmission of a pathogenic mitochondrial DNA 8993T>G mutation. METHODS: A Chinese family affected with Leigh syndrome which had attended the Reproductive Medicine Centre of the First Affiliated Hospital of Anhui Medical University in September 2021 was selected as the study subject. Controlled ovarian hyperstimulation was carried out for the proband after completing the detection of the mitochondrial DNA 8993T>G mutation load among the pedigree members. Mature MII oocytes were inseminated by intracytoplasmic sperm injection (ICSI), cultured in vitro for 5 to 6 days to the blastocyst stage, and trophoblastocytes were obtained by microbiopsy. Mitochondrial DNA testing (PGT-MT) and chromosomal aneuploidy (PGT-A) analyses were carried out after whole-genome amplification, and the embryos with zero mutation load were selected for transfer. Amniotic fluid and umbilical cord blood samples were collected during middle pregnancy and after birth respectively for mitochondrial DNA testing to verify the reliability of embryo screening. As an attempt, PB1 with good morphology of MII oocytes was selected for transfer into the enucleated oocytoplasm from healthy donors, followed by ICSI fertilization, blastocyst culture and PGT of embryos using the same procedure. This study has been approved by the Ethics Committee of the First Affiliated Hospital of Anhui Medical University (No. 2021zhyx-B12). RESULTS: An antagonist protocol was used for ovarian stimulation, and a total of 19 oocytes were obtained, of which 14 MII were fertilized by ICSI, and 2 had developed into blastocysts. PGT-MT was carried out on biopsied trophoblastocytes, in which the mitochondrial DNA 8993T>G mutation load was not detected in one embryo, the other was 100% mutated, and the mutation loads of the remaining unfertilized eggs and developmentally arrested embryos ranged from 0% ~ 100%, presenting a clear biased distribution. With fully informed consent, one PGT-MT zero mutation load blastocyst was transferred and clinical pregnancy was achieved. Mitochondrial DNA and chromosomal testing of amniotic fluid cells during middle pregnancy had revealed no abnormalities. The proband had delivered a healthy boy through Caesarean section at 39⁺⁵ weeks of gestation, and no mutation was detected in the cord blood sample. Five well-formed PBs from 14 eggs were selected for PB1 transfer, followed by ICSI and culture, and two of the reconstituted embryos had formed blastocysts, with none of the above mutations detected in the biopsied samples. CONCLUSION The PGT-MT technology can help families affected with mitochondrial diseases to have healthy offspring. PB1 transfer in combination with ICSI and PGT-MT holds the promise of turning waste into treasure and providing an alternative means of fertility for such families.
Humans ; Preimplantation Diagnosis/methods* ; Female ; DNA, Mitochondrial/genetics* ; Genetic Testing/methods* ; Pregnancy ; Mitochondrial Diseases/genetics* ; Polar Bodies ; Adult ; Feasibility Studies ; Sperm Injections, Intracytoplasmic/methods* ; Embryo Transfer/methods* ; Mutation ; Male ; Blastocyst/metabolism* ; Pedigree

OBJECTIVE: To explore the results of four types of Urea cycle disorders (UCDs) in newborns from the Xuzhou region, assess the efficacy of newborn screening by tandem mass spectrometry (MS/MS), and analyze their genetic characteristics. METHODS: A retrospective analysis was performed using tandem mass spectrometry to screen for inherited metabolic disorders in 691 712 newborns at the Maternal and Child Health Care Hospital of Xuzhou from November 2015 to December 2023. Ten children (cases 1-10) were diagnosed with Ornithine transcarbamylase deficiency (OTCD), Carbamoylphosphate synthase 1 deficiency (CPS1D), Arginase deficiency (ARGD), and Argininosuccinate synthase deficiency (ASSD) based on MS/MS and genetic testing. This study was approved by the Medical Ethics Committee of Xuzhou Maternity and Child Health Care Hospital (Ethics No.XZFY2024-051K-01J). RESULTS: A total of 691 712 neonates were screened for UCDs using MS/MS, which identified 1 237, 1 237, 510, and 1 009 initial positive cases for OTCD, CPS1D, ASSD, and ARGD, respectively. After genetic testing, 1 case of OTCD, 1 case of CPS1D, 1 case of ASSD, and 7 cases of ARGD were confirmed. The overall positive predictive value for these four UCDs was 0.362%. Among the 10 diagnosed UCD cases, four novel variants were identified, which included OTC: c.1024C>A (p.L342M) and ASS1: c.826A>G (p.M276V), c.695C>T (p.P232L) and c.694C>T (p.P232S). Bioinformatic analysis has rated these as variants of uncertain clinical significance or likely pathogenic based on guidelines from the American College of Medical Genetics and Genomics (ACMG). CONCLUSION The incidence of four UCDs in neonates from the Xuzhou area is relatively low, and there is a correlation between genetic variants and clinical phenotypes. For novel variants with uncertain clinical significance or suspected pathogenicity, their pathogenicity should be clarified in conjunction with clinical and biochemical indicators. The four novel pathogenic variants of UCDs identified in this study have enriched the mutational spectrum of UCDs-associated genes in the Xuzhou region.
Humans ; Infant, Newborn ; Tandem Mass Spectrometry/methods* ; Urea Cycle Disorders, Inborn/diagnosis* ; Neonatal Screening/methods* ; Genetic Testing/methods* ; Female ; Retrospective Studies ; Male ; Ornithine Carbamoyltransferase Deficiency Disease/diagnosis* ; Mutation ; Carbamoyl-Phosphate Synthase (Ammonia)/genetics* ; Ornithine Carbamoyltransferase/genetics*

OBJECTIVE: To explore the clinical features and genetic characteristics of three patients with Infantile liver failure syndrome type 2 (ILFS2). METHODS: Three children who were diagnosed with ILFS2 at the Children's Hospital Affiliated to Zhengzhou University from February 2023 to February 2024 were selected as the study subjects. Clinical data of the children were collected. Peripheral blood samples of the children and their parents were collected and subjected to whole exome sequencing (WES). Candidate variants of the NBAS gene were verified by Sanger sequencing. This study was approved by the Ethics Committee of the Children's Hospital Affiliated to Zhengzhou University (Ethics No. 2024-k-069). RESULTS: The three children had presented with fever-triggered recurrent acute liver failure. All of them were found to harbor compound heterozygous variants of the NBAS gene, including c.3596G>A and c.1181A>T in child 1, c.2617C>T and c.2T>C in child 2, and c.3596G>A and c.2817_2818insT in child 3. Among these, the c.1181A>T and c.2817_2818insT variants were unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), they were respectively classified as variants of uncertain significance (PM2_Supporting+PM3+PP3) and pathogenic (PVS1+PM2_Supporting+PM3). CONCLUSION Combined with the patient's clinical phenotype, the compound heterozygous variants of the NBAS gene probably underlay the pathogenesis of ILFS2 in the three children. For children with fever-related acute liver failure of unknown causes, the possibility of this disease should be suspected, and genetic testing may facilitate the diagnosis. Early diagnosis and timely intervention can significantly improve the prognosis. Discoveries of the c.1181A>T and c.2817_2818insT variants have enriched the mutational spectrum of the NBAS gene.
Humans ; Exome Sequencing ; Genetic Testing/methods* ; Liver Failure, Acute/etiology* ; Mutation ; Child ; Adult ; Neoplasm Proteins

OBJECTIVE: To explore the clinical phenotype, pregnancy outcome and follow-up of fetuses with 15q11.2BP1-BP2 microdeletions in order to provide a basis for prenatal and reproductive consultation. METHODS: From March 2019 to December 2023, 20 fetuses who were diagnosed with 15q11.2BP1-BP2 microdeletion syndrome at the Prenatal Diagnosis Center of General Hospital of Ningxia Medical University were selected as the study subjects. Results of genetic testing and ultrasound examination, outcome of pregnancy, and postnatal follow-up were retrospectively analyzed. This study has been approved by the Ethics Committee of General Hospital of Ningxia Medical University ([2020]0520B). RESULTS: None of the 20 fetuses was found to have chromosomal abnormality, whilst all were found to harbor a 15q11.2 BP1-BP2 microdeletion by low-depth whole genome sequencing (CNV-seq). The range of deletions was determined as 0.26 ~ 0.87 Mb, and all were rated as pathogenic CNVs. Three fetuses had abnormal ultrasound findings, including 1 with widened renal pelvis, 1 with agenesis of corpus callosum, and 1 with nuchal fold thickening. Parental verification in 10 couples verified that two fetal deletions were de novo, whilst the remaining eight were inherited from a phenotypically normal parent. Following genetic counseling, three couples had opted to terminate the pregnancy, whilst the remaining 17 had continued with the pregnancy until delivery. The 17 liveborns were followed up for 2 months to 5 years, with no obvious abnormality in growth and development noted. CONCLUSION CNV-seq plays an important role in the prenatal diagnosis of 15q11.2 BP1-BP2 microdeletions. Such deletions may not always lead to disease phenotypes. Individualized consultation and long-term follow-up, in combination with intrauterine ultrasound and parental verification are necessary.
Humans ; Female ; Pregnancy ; Chromosomes, Human, Pair 15/genetics* ; Genetic Counseling ; Prenatal Diagnosis ; Chromosome Deletion ; Adult ; Fetus/abnormalities* ; Retrospective Studies ; Pregnancy Outcome ; Ultrasonography, Prenatal ; Genetic Testing ; DiGeorge Syndrome/diagnosis* ; Male

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

OBJECTIVE: To explore the genotype-phenotype correlation in a Charcot-Marie-Tooth type 2A2A (CMT2A2A) pedigree and to provide genetic counseling for its subsequent pregnancies. METHODS: A Chinese pedigree presenting with "lower limb muscle atrophy and movement disorders" at the Prenatal Diagnosis Center of Xuzhou Central Hospital between January and August 2024 was selected as the study subject. Relevant clinical data were collected from the pedigree members. Peripheral blood samples from affected individuals, and amniotic fluid and/or chorionic villus samples were obtained for DNA extraction. Whole exome sequencing (WES) was carried out. Candidate variants were verified by Sanger sequencing. Pathogenicity assessment and bioinformatic analysis were conducted. This study was approved by the Medical Ethics Committee of Xuzhou Central Hospital (Ethics No. XZXY-LK-20240111-0019). RESULTS: All affected individuals in this pedigree were females, whom included the proband, her mother, and her first daughter. Earlier age of onset was associated with more severe lower limb atrophy. A heterozygous missense variant of the MFN2 gene, namely c.314C>T (p.Thr105Met), was identified in the proband, her mother, daughter, and the third fetus from a re-marriage. The same variant was absent in her elder brother, current husband, and her fourth fetus. Based on the guidelines from American College of Medical Genetics and Genomics (ACMG) and recommendations from Clinical Genome Resources (ClinGen), the variant was classified as pathogenic (PP1_Strong+PM1+PS3+PS4_Moderate+PP3_Moderate+PM2_Supporting). Analyses with PROVEAN and Mutation Taster had categorized the variant as "deleterious" and "disease-causing", respectively. Analysis with Uniprot and Jalview showed that the affected amino acid residue is conserved across multiple species. ChEBI software predicted that the variant may alter the polarity of the 105th amino acid residue. CONCLUSION The c.314C>T (p.Thr105Met) missense variant of the MFN2 gene probably underlie the CMT2A2A in this pedigree. Above finding has enabled prenatal diagnosis and genetic counseling for its subsequent pregnancies.
Adult ; Female ; Humans ; Male ; Charcot-Marie-Tooth Disease/genetics* ; East Asian People/genetics* ; Exome Sequencing ; Genetic Testing/methods* ; GTP Phosphohydrolases/genetics* ; Mitochondrial Proteins/genetics* ; Mutation, Missense ; Pedigree