OBJECTIVE: To provide preimplantation genetic testing (PGT) for a patient with Incontinentia pigmenti (IP) due to IKBKG gene variant but without family samples through construction of single nucleotide polymorphism (SNP)-based haplotype by Long-read sequencing (LRS) technology. METHODS: A female IP patient with a heterozygous IKBKG c.1167dup variant but without family genetic data who sought genetic counseling at Women and Children' Hospital of Ningbo University in November 2021 was selected as the study subject. The IKBKG gene has a highly homologous pseudogene IKBKGP1. Genomic DNA was extracted from peripheral blood samples from the couple, and LRS was used to obtain informative SNP loci flanking the variant locus, enabling the construction of SNP haplotype with a long segment spanning from the non-homologous region of IKBKG to the variant site. Trophoblast cells were biopsied from blastocysts fertilized through intracytoplasmic sperm injection, and next-generation sequencing (NGS) was used to determine the SNP information of the embryos. Linkage analysis with the parental SNP haplotypes was conducted to detect the carrier status of the embryos and exclude chromosomal aneuploidies. Sanger sequencing was carried out to validate the result. A euploid embryo without the pathogenic variant was selected for transfer. Prenatal diagnosis was carried out by amniocentesis at mid-trimester to verify the result of PGT tests, and follow-up was conducted after the baby was born. This study has been approved by the Ethics Committee of Women and Children's Hospital of Ningbo University (Ethics No. EC2023-094). RESULTS: A total of seven blastocysts were tested, and PGT results indicated that two embryos were euploid and did not carry the pathogenic variant. One euploid embryo was transferred, which resulted in a singleton pregnancy. Amniocentesis at 24 weeks of gestation confirmed that the status of fetal IKBKG gene, and its chromosomal status was consistent with the PGT results. A healthy male infant was born at 38+6 weeks of gestation. CONCLUSION For IP patients with de novo mutation or without family genetic samples, PGT with LRS can directly construct the SNP-based haplotype while avoiding interference from pseudogenes, providing an effective strategy for PGT.
Female ; Humans ; Male ; Pregnancy ; Genetic Testing/methods* ; Haplotypes/genetics* ; High-Throughput Nucleotide Sequencing/methods* ; I-kappa B Kinase/genetics* ; Incontinentia Pigmenti/diagnosis* ; Polymorphism, Single Nucleotide/genetics* ; Preimplantation Diagnosis/methods* ; Infant, Newborn

OBJECTIVE: To apply optical genome mapping (OGM) technique for the analysis of genetic etiology in two rare families with complex chromosomal rearrangements (CCRs) and to provide precise reproductive guidance to them. METHODS: Two Chinese families diagnosed with chromosomal rearrangements by chromosomal microarray analysis (CMA) or whole-exome sequencing (WES) between June and December 2023 at the Affiliated Women and Children's Hospital of Ningbo University were selected as the study subjects. In both cases, unbalanced chromosomal translocations were suspected. Clinical data were collected, and peripheral blood from the couple, amniotic fluid sample and aborted fetal tissue was subjected to combined G-banding karyotyping and OGM for comprehensive genetic analysis. This study has been approved by the Medical Ethics Committee of the Hospital (Ethics No.: EC2023-094). RESULTS: In family 1, the fetus was signaled to have abnormal chromosome 7 by non-invasive prenatal testing (NIPT), prompting amniocentesis and CMA detection. In family 2, a pregnancy loss had occurred at 10 weeks' gestation, and trio-WES was carried out. Both fetuses were found to harbor copy number variations (CNVs) suggestive of unbalanced CCRs. Further analysis with OGM has revealed that, in family 1, an unbalanced rearrangement involving chromosomes 7, 8, and 10 was carried by the fetus and the pregnant woman, which has formed der(8) and der(10) derivative chromosomes. In family 2, a maternal CCR was found, which involved chromosomes 2 and 13 with seven breakpoints, resulting in unbalanced fetal CNVs. After genetic counseling, family 1 opted to continue with the pregnancy, considering the woman's normal appearance and inheritance of the rearrangement. For both families remained to have a risk for unbalanced rearrangements in subsequent pregnancies, preimplantation genetic testing (PGT) was recommended. CONCLUSION In both families, the OGM has precisely delineated the genetic basis of fetal CNVs and mapped the maternal CCR breakpoints, providing critical insights for genetic counseling and reproductive decision-making.
Adult ; Female ; Humans ; Male ; Pregnancy ; Chromosome Aberrations ; Chromosome Disorders/genetics* ; Chromosome Mapping/methods* ; Genetic Testing/methods* ; Pedigree ; Prenatal Diagnosis/methods* ; Translocation, Genetic

OBJECTIVE: To determine the prevalence of GJB2 gene c.109G>A (p.V37I) variant among infants with congenital hearing loss and analyze the initial audiological characteristics of children harboring the variant, compare the audiometric difference among individuals with various genotypes, and explore genetic and audiological manifestations of the affected families. METHODS: One hundred twenty six infants diagnosed with congenital hearing loss at the Neonate Screening Center of Ningbo City from June 2021 to December 2024 were selected as the study subjects. The neonates, in addition with members from 16 of their families, had undergone genetic screening for variants of 208 hotspot sites within 24 deafness-associated genes. For cases identified with monoallelic variants and concurrent hearing loss, the full GJB2 gene was sequenced. Meanwhile, a retrospective analysis was carried out on 23 children whom were confirmed to have hearing loss and the c.109G>A variant by whole exome sequencing from March 2022 to December 2024. And 102 children who were excluded to have hearing loss and pathogenic variants by whole exome sequencing were selected as normal controls. Audiological features of individuals harboring the c.109G>A variant were compared. This study has been approved by the Medical Ethics Committee of The Affiliated Women and Children's Hospital of Ningbo University (Ethics No.: EC2023-009). RESULTS: For the 126 infants with congenital hearing loss, prospective screening has identified 58 (46.03%) to harbor the c.109G>A variant. These included 38 homozygotes and 16 compound heterozygotes. Retrospective review of the 23 c.109G>A positive children has identified 15 as homozygotes and 8 as compound heterozygotes. Genetic testing of the 16 pedigrees has identified 7 homozygotes and 1 compound heterozygote. For the homozygotes combined (n = 53), 96.2% exhibited bilateral symmetric hearing loss, with 78.3% showing high-frequency sloping patterns, and 98.1% having a hearing threshold ranging from 20 to 65 dB. For the compound heterozygotes combined (n = 24), 95.8% showed symmetric loss, with 59.4% having high-frequency sloping, and 97.9% had a hearing threshold ranging from 20 to 65 dB. Both groups showed significantly elevated ABR/PTA thresholds compared with the normal controls (P = 0.000). The compound heterozygous group had higher ABR thresholds (43.3 ± 15.0 dB nHL) compared with the homozygous group (39.1 ± 12.0 dB nHL, P = 0.005). CONCLUSION Infants harboring the GJB2 c.109G>A variant primarily manifest as mild-to-moderate, symmetric, high-frequency sloping hearing loss. Nearly one-third of affected children have thresholds between 20 to 35 dB nHL, suggesting that ABR > 35 dB nHL alone may underestimate the hearing impairment in this population. Compared with homozygotes, compound heterozygotes with the the GJB2 c.109G>A variant can confer a more severe hearing loss.
Humans ; Connexin 26/genetics* ; Female ; Male ; Infant, Newborn ; Infant ; Hearing Loss/genetics* ; Retrospective Studies ; Child, Preschool ; Child ; Genotype ; Connexins/genetics* ; Mutation

OBJECTIVE: To assess the value of Optical genome mapping (OGM) for the verification of chromosomal structural variations among patients undergoing assisting reproduction. METHODS: A retrospective analysis was carried out on the clinical data of 12 patients presented at the Reproductive Center of Ningbo University Women and Children's Hospital from October 2022 to October 2024. All patients had undergone OGM testing due to suspection of structural variants by chromosomal karyotyping or a suggestive medical history. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: EC2024-148). RESULTS: Among the 12 patients verified by OGM, one (8.3%) was in keeping with the result of chromosomal karyotyping. Revised karyotypes were confirmed in seven cases (58.3%), including four with complex chromosomal rearrangements. Structural variation was excluded in three cases (25.0%). Of note, OGM has identified a previously undetected cryptic balanced translocation, i.e., ogm[GRCh38] t(7;12)(q36.3;q24.23)(157511190_157523142;119205703_119198409). CONCLUSION OGM can serve as an auxiliary diagnostic technique to conventional karyotyping and enable validation of suspected structural variations in those with ambiguous karyotype results or a history of adverse pregnancies. This can provide more precise genetic diagnosis for patients undergoing assisted reproduction and selection of clinical intervention strategies.
Humans ; Female ; Adult ; Retrospective Studies ; Karyotyping ; Reproductive Techniques, Assisted ; Chromosome Mapping/methods* ; Chromosome Aberrations

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.
Humans ; Abortion, Habitual/etiology* ; Female ; Pregnancy ; Male ; DNA Copy Number Variations/genetics* ; Adult ; Karyotyping ; Pedigree ; Gene Rearrangement ; Chromosome Mapping

Objective:To explore the genetic etiology for a child with Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 6 (PEOA6).Methods:A child who had attended the Women and Children′s Hospital Affiliated to Ningbo University on 7 August, 2023 was selected as the study subject. Clinical data of the child were analyzed retrospectively. The child and her parents were subjected to whole exome sequencing (WES), and candidate variant was verified by Sanger sequencing and bioinformatic analysis. This study was approved by Medical Ethics Committee of the Women and Children′s Hospital Affiliated to Ningbo University (Ethics No. EC2020-048).Results:The child, a 7-year-old female, had presented with limb muscle pain, amyosthenia, significantly increased creatine kinase, congenital diaphragmatic hernia and recurrent respiratory tract infections. WES revealed that she has harbored a heterozygous c. 1590G>C (p.L530F) variant of the DNA2 gene, which was verified to have a de novo origin by Sanger sequencing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.1590G>C was rated as a likely pathogenic variant (PS2+ PM2_Supporting+ PP3). Conclusion:The c.1590G>C (p.L530F) variant of the DNA2 gene probably underlay the PEOA6 in this child.

Objective:To explore the clinical features and genetic etiology of a fetus with 15q11q13 complex duplication syndrome.Methods:A fetus diagnosed with 15q11q13 duplication syndrome at Ningbo Women and Children′s Hospital on April 19, 2023 was selected as the study subject. Clinical data was collected, and the fetus was subjected to invasive prenatal diagnosis including G-banded karyotyping and chromosomal microarray analysis(CMA). Following the discovery of chromosomal duplication, trio-whole exome sequencing was carried out to exclude single base variants and confirm the parental original of the duplication. Optical genome mapping was also performed to delineate the structural arrangement of the duplication. Relevant literature was searched in the PubMed, Wanfang Medical Network and CNKI databases using "15q11q13", "duplication", "hexasomy" and "Six fold repetition" as the key words from January 1, 2000 to August 1, 2023 for a review of previously reported 15q11q13 hexasomy cases. This study was approved by Medical Ethics Committee of the Ningbo Women & Children′s Hospital (Ethics No. EC2020-048).Results:The fetus was found to have a mosaicism karyotype of 48, X?, + mar, + idic(15)(q13)[33]/ 47, X?, + idic(15)(q13)[17]. CMA and trio-WES have all shown a six-fold duplication in the PWS/AS critical region (PWACR) at 15q11.2q13.2 and quadruple duplication of 15q13.2q13.3 region, which have derived from its mother and formed supernumerary marker chromosomes (SMCs). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the 15q11.2q13.2 sixfold duplication was classified as pathogenic, whilst the 15q13.2q13.3 quadruple duplication was classified as variant of uncertain significance. Literature search has identified 11 cases of 15q11q13 duplication involving hexasomy of the PWACR, with all cases showing mental retardation, language delay and hypotonia, and most of them also had motor retardation, epilepsy and mild facial dysmorphism.Conclusion:Hexasomy for the PWACR combined with tetrasomy of 15q13.2q13.3 probably underlay the left hand polydactyly, polyhydramnios and intrauterine growth retardation in this fetus.

OBJECTIVE: To explore the strategies of prenatal diagnosis and genetic counseling for fetuses of two families with large deletions of 13q21. METHODS: Two singleton fetuses who were diagnosed with chromosome 13 microdeletions by non-invasive prenatal testing (NIPT) at Ningbo Women and Children's Hospital in March 2021 and December 2021 respectively were selected as the study subjects. Chromosomal karyotyping and chromosomal microarray analysis (CMA) were carried on amniotic samples. Peripheral blood samples were collected from the two couples for CMA assay to determine the origin of abnormal chromosomes identified in the fetuses. RESULTS: The karyotypes of the two fetuses were both normal. CMA revealed that they have respectively harbored heterozygous deletions spanning 11.935 Mb at 13q21.1q21.33 and 10.995 Mb at 13q14.3q21.32, which were respectively inherited from their mother and father. Both deletions had low gene density and lacked haploinsufficient genes, and were predicted to be likely benign variants based on database and literature search. Both couples had opted to continue with the pregnancy. CONCLUSION The deletions of the 13q21 region in both families may be of benign variants. As the follow-up time was short, there was no sufficient evidence for the determination of pathogenicity, though our finding may still provide a basis for the prenatal diagnosis and genetic counseling.
Pregnancy ; Child ; Female ; Humans ; Pedigree ; East Asian People ; Prenatal Diagnosis ; Chromosome Aberrations ; Karyotyping ; Microarray Analysis ; DNA Copy Number Variations

OBJECTIVE: To explore the types of NF1 gene variants and clinical characteristics among patients with Neurofibromatosis type I (NF1). METHODS: Clinical data of 12 patients diagnosed at Ningbo Women and Children's Hospital between December 2019 and May 2022 were retrospectively analyzed. The probands and their family members were subjected to high-throughput sequencing, and candidate variants were verified by Sanger sequencing and chromosome microarray analysis. RESULTS: The 12 patients had ranged from 4 months to 27 years old, with a male-to-female ratio of 2 : 1. Cafè-au-lait spots were found in all patients. 83.3% of them also had axillary and/or inguinal freckling, 58.3% had neurofibromas, and 16.7% had congenital pseudarthrosis of the tibia. Five types of NF1 gene variants were identified in the patients, including 5 nonsense variants, 4 frameshift variants, 1 missense variant, 1 splice variant, 1 large deletion involving the whole gene. Six patients were found to harbor de novo variants, 2 had inherited the variants from their parents, and 4 were not verified for their parental origin. The c.3379del (p.Thr1127Glnfs*15) and c.6628_6629del (p.Glu2210Thrfs*10) variants were unreported in literature and databases. CONCLUSION Most NF1 patients may present with Cafè-au-lait spots initially and are due to pathogenic variant of the NF1 gene. High-throughput sequencing can efficiently identify such variants among the patients and enable the definite diagnosis.
Child ; Humans ; Female ; Male ; Neurofibromatosis 1/diagnosis* ; Cafe-au-Lait Spots/diagnosis* ; Genes, Neurofibromatosis 1 ; Retrospective Studies ; Frameshift Mutation

OBJECTIVE: To explore the genetic etiology of Vici syndrome in a Chinese family. METHODS: Whole exome sequencing (WES) technology was used to detect gene variants in a fetus of abnormal ultrasonic structure without abnormalities in routine chromosome karyotype analysis and SNP-array. Sanger sequencing and bioinformatics prediction were performed for the suspected variants of the fetus and parents. RESULTS: The fetus and the elder sister have carried c. 2427delC (p.T809fs) and c.1886A>T (p.E629V) compound heterozygous variants of the EPG5 gene, which were respectively inherited from their mother and father. Neither variant was reported previously. According to ACMG guidelines, the c.2427delC variant was predicted as pathogenic, while the c.1886A>T variant was of uncertain significance. PolyPhen-2 and PROVEAN software indicated that c.1886A>T variant was probably damaging. CONCLUSION The c.2427delC and c.1886A>T variants of the EPG5 gene probably underlie the pathogenesis of the Vici syndrome in this family. Above finding has enriched the variational spectrum of EPG5 gene and provided a basis for genetic counseling and prenatal diagnosis for the family.
Aged ; Agenesis of Corpus Callosum ; Autophagy-Related Proteins ; Cataract ; Female ; Humans ; Mutation ; Pregnancy ; Vesicular Transport Proteins/genetics* ; Whole Exome Sequencing