Objective: To analyze the clinical and genetic characteristics of a Chinese pedigree affected with congenital Isolated growth hormone deficiency (IGHD).
Methods: A pedigree presenting with Pituitary stalk interruption syndrome (PSIS) (including the proband, his two younger sisters and both parents) who had visited the Capital Institute of Pediatrics Affiliated to Capital Medical University in September 2020 was selected as the study subject. Clinical data were collected. Peripheral blood samples were collected from the proband and his family members. Following the extraction of genomic DNA, whole-exome sequencing (WES) was carried out, and candidate variants were validated by Sanger sequencing. The pathogenicity of the candidate variants was classified based on guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of the Institute Pediatrics of Capital Medical University (Ethics No.: SHERLL2025033).
Results: The proband and one younger sister (Ⅱ3) presented with growth retardation, short stature, and a doll-like facies. Another younger sister (Ⅱ2) and both parents had normal heights and appearance. Sanger sequencing confirmed that the proband and his younger sister (Ⅱ3) both harbored compound heterozygous variants of the GHRHR gene, namely c.776C>A (p.T259K) and c.1166G>A (p.R389Q). The other younger sister (Ⅱ2) and the parents were heterozygous carriers. The c.1166G>A (p.R389Q) variant was unreported previously. Based on the guidelines from the ACMG, it was classified as variant of uncertain significance (PM2_Supporting+BP4). Bioinformatics analysis indicated a deleterious effect on the protein function.
Conclusion: Variants of the GHRHR gene probably underlay the pathogenesis of IGHD in this pedigree. Above finding has provided a basis for the clinical diagnosis and genetic counseling for this family.
Objective: To analyze the distribution frequency and characteristics of HLA-A and HLA-B loci in patients with immune-mediated Platelet transfusion refractoriness (iPTR) in order to provide data support for investigating HLA gene matching strategies for platelet transfusion and improving transfusion efficacy.
Methods: A total of 532 iPTR patients who applied for gene matched platelet at the Blood Center of Zhejiang Province between January 2020 and June 2024 were selected as the study subjects. Genomic DNA was extracted from peripheral blood samples from the patients, and the HLA-A and HLA-B loci were detected simultaneously using a PCR-sequence specific oligonucleotide probe method (PCR-SSO) and PCR-sequence based typing (PCR-SBT). Statistical methods were used to analyze the distributions of HLA-A and HLA-B antigens and genotypes on the platelet surface of the patients. An analysis of the differences was conducted to compare the results with the Common and Well-Documented (CWD) allele in the Chinese population from the China Marrow Donor Program (CMDP) database. This study was approved by the Medical Ethics Committee of the Blood Center of Zhejiang Province (Ethics No.: Provincial Blood Center Ethics Review 2023Yan No.004).
Results: Among the 532 iPTR patients, 19 HLA-A antigens (including 32 HLA-A alleles) and 37 HLA-B antigens (including 64 HLA-B alleles) were detected. The antigens with the highest frequencies were A2, A11, A24, and B46, B60, B58, with the combined distribution frequency of the top three antigens reaching 71.43% and 36.94%, respectively. The most prevalent alleles of the HLA-A and HLA-B loci were A*11:01, A*24:02, A*02:07 and B*46:01, B*40:01, B*58:01. The frequencies of common alleles A*01:01, A*02:07, A*11:02, A*30:01 and B*13:02, B*27:04, B*40:01, B*44:03, B*46:01 showed significant differences (P < 0.05) compared to the normal population in the CWD table (version 2.4) of CMDP.
Conclusion: The HLA-A and HLA-B genes of the iPTR patients showed great divergence, and the distribution frequencies of certain alleles have differed significantly from those of the normal population. This study has provided genetic data for exploring the molecular mechanism underlying iPTR, which is of significant clinical importance for searching HLA gene matched donors.
Objective: To analyze a Chinese pedigree affected with Non-syndromic autosomal recessive deafness type 12 (NFNB12), validate the function of candidate variants, and explore the underlying mechanisms.
Methods: A NFNB12 pedigree presented at Henan Provincial People's Hospital in February 2023 was selected as the study subject. Whole exome sequencing (WES) was carried out, and candidate variant was verified by Sanger sequencing of the pedigree members. Reverse transcription polymerase chain reaction (RT-PCR) was used to determine the level of mRNA transcription in the peripheral blood samples from the pedigree members, and protein expression was evaluated with Western blotting assay. This study was approved by Medical Ethics Committee of Henan Provincial People's Hospital (Ethics No.: 2019-134).
Results: WES analysis revealed that the proband has harbored homozygous c.6688delG (p.Ala2230Profs*4) variant of the CDH23 gene, for which both parents were identified as heterozygous carriers. RT-PCR analysis demonstrated the sole presence of the variant mRNA in the proband, and both the variant and wild-type mRNAs in both parents. Furthermore, Western blotting analysis indicated that the proband had exclusively expressed the truncated CDH23 protein, while both the normal and truncated forms of the protein were noted in her parents.
Conclusion: The c.6688delG (p.Ala2230Profs*4) variant of the CDH23 gene probably underlay the pathogenesis of NFNB12 in this pedigree. The loss of function of the CDH23 gene resulting from this variant is not related with nonsense-mediated mRNA decay, but rather production of a truncated protein. Above finding has not only enriched the mutational spectrum of the CDH23 gene and offered a method for investigating the function of its variants using peripheral blood samples, but also delineated the molecular basis for the loss of function, which has provided crucial evidence for genetic counseling and prenatal diagnosis for this family.
Objective: To explore the clinical characteristics and genetic etiology of a patient with Fliedner-Zweier syndrome (FZS).
Methods: A pregnant woman who was diagnosed with FZS at the Affiliated Women and Children's Hospital of Ningbo University in November 2023 for "intellectual disability, epilepsy, delayed language development and facial abnormalities" was selected as the study subject. Peripheral blood samples were collected from the woman and her husband, whilst amniotic fluid sample was obtained from the fetus. Following extraction of genomic DNA, whole-exome sequencing (WES) and chromosomal karyotyping analysis were performed. Candidate variant was validated by Sanger sequencing. Pathogenicity of the variant was classified 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.: EC2023-094).
Results: The proband, a 23-year-old woman, was at 19+2 weeks of gestation and had a history of epilepsy, mild intellectual disability, delayed language development, and subtle facial dysmorphism. Chromosomal analysis showed the she has a normal karyotype. WES revealed that the woman and her fetus both harbored a heterozygous c.1489C>T (p.Gln497Ter) nonsense variant of the SCAF4 gene, which was verified by Sanger sequencing as de novo. Based on the ACMG guidelines, the variant was classified as pathogenic (PVS1+PM2_supporting+PS2_supporting). According to pre-set search strategy, five articles were retrieved. Together with the patient in this study, a total of 69 FZS patients were involved (including 7 from China). The main clinical features have included intellectual disability, epilepsy, behavioral abnormalities, and facial dysmorphism.
Conclusion: The heterozygous c.1489C>T (p.Gln497Ter) variant of the SCAF4 gene probably underlyay the FZS in this patient. Above finding has expanded the mutational spectrum of the SCAF4 gene.
Objective: To investigate the clinical characteristics and genetic etiology of a male with a normal phenotype and SRY gene-positive 46,XX/46,XY tetrazoospermia chimerism.
Methods: A male patient with an abnormal peripheral blood chromosomal karyotype detected at the Infertility Center of Taizhou Hospital of Zhejiang Province on December 2, 2013 was selected as the study subject. Peripheral venous blood samples were collected from the proband and his family members, together with a semen sample from the proband. Chromosomal karyotype analysis, red blood cell blood group identification, chromosomal microarray analysis (CMA), fluorescence in situ hybridization (FISH), sex-determining region Y (SRY) gene detection, and short tandem repeat (STR) microsatellite marker analysis were performed on the peripheral venous blood sample from the proband. Routine semen analysis, sperm FISH, and STR testing were also conducted. STR verification was performed on both parents. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: k20201009).
Results: The proband, a 37-year-old male, had normal secondary sexual characteristics and external genitalia development. The chromosomal karyotype of his peripheral blood sample was 46,XX[94]/46,XY[6]. ABO blood group typing was positive for Rh(D) type O and negative for Rh(D) type A, indicating the presence of two red blood cell populations. CMA result was arr[GRCh37](1-22)×2,(XX)×1. Autosomal and X chromosome SNP genotypes were BB-BB, AB-AB, and AA-AA, making it impossible to identify homozygous/heterozygous chimerism. FISH detection of interphase nuclei showed nuc ish XX[92]/XY[8]. Testing of the SRY gene was positive. STR analysis showed a single X peak (no Y peak) at the AMEL locus, 10/12 at the Penta D locus, and no third allele at other loci. Routine semen analysis were normal. Sperm FISH detection showed haploid nuclei nuc ish X[53]/Y[47]. Sperm STR analysis revealed an X/Y bimodal distribution at the AMEL locus and a 9/14 distribution at the Penta D locus, with no third allele observed at other loci. Above results suggested that the proband's blood and germ cell lines had originated from a heterozygous chimera formed by the fusion of two different zygotes.
Conclusion: Combined genetic techniques confirmed that the proband's peripheral blood AMEL genotype is X/X, while the sperm is X/Y. The Penta D locus showed a bi-allelic heterozygous pattern of 10/12 in the peripheral blood sample and 9/14 in the sperm sample, suggesting that the proband is a tetrazygotic chimera resulted from the fusion of 46,XX/46,XY zygotes.
Objective: To explore the clinical features and genetic basis of a male patient with Kennedy disease(KD) presenting as secondary infertility.
Methods: A male patient who had presented at Yantai Yuhuangding Hospital in August 2023 for secondary infertility for 5 years was selected as the study subject. Clinical data, laboratory findings, and auxiliary examination of the patient were collected. Peripheral blood samples were obtained from the patient and his family members. Following DNA extraction, whole-exome sequencing (WES) was carried out. Pathogenicity of candidate variant was predicted by bioinformatics analysis. Fluorescence probe PCR-capillary electrophoresis was employed to analyze the trinucleotide CAG repeat sequence variation in the AR gene to rule out dynamic mutation. This study was approved by the Ethics Committee of Yantai Yuhuangding Hospital (Ethics No.: 2024-697).
Results: The patient had presented with non-obstructive azoospermia and elevated androgen sensitivity index. Ultrasound scan indicated small testicular volume and seminal vesicle atrophy. WES and bioinformatics analysis revealed abnormal amplification in the patient's AR gene. Fluorescence probe PCR and capillary electrophoresis confirmed that both the proband and his nephew had harbored 52 CAG trinucleotide repeats in exon 1 of the AR gene, confirming the diagnosis of KD. The proband's mother, elder sister, and daughter were identified as carriers of the variant, while his second elder sister did not carry the mutation.
Conclusion: As a rare X-linked recessive genetic disease, KD mainly manifests with muscle weakness, myasthenia gravis and myofascial tremor, while cases with infertility and non-obstructive azoospermia as the initial symptoms are rare and can be easily missed. Diagnosis made by genetic testing needs to be taken seriously by the clinicians.
Objective: To investigate the molecular mechanism for a family with Hereditary coagulation factor Ⅻ (FⅫ) deficiency.
Methods: The proband, a 63-year-old female, was admitted to the First Affiliated Hospital of Wenzhou Medical University in August 2024 for lumbar disc herniation. Coagulation tests, including prothrombin time (PT), activated partial thromboplastin time (APTT), and FⅫ activity (FⅫ:C), were carried out for the proband and her family members (9 individuals from three generations) using a one-stage clotting assay. The level of FⅫ antigen (FⅫ:Ag) was determined with an Enzyme-linked immunosorbent assay (ELISA). Sanger sequencing was conducted to identify potential variants in the F12 gene. Multiple in silico tools were used to predict the conservation, hydrophobicity, and structural impact of the identified variants. Recombinant expression plasmids were constructed and transiently transfected into HEK293T cells. The recombinant FⅫ protein was analyzed using Western blotting (WB) and ELISA. This study was approved by the Ethics Committee of the First Affiliated Hospital of Wenzhou Medical University (Ethics No.: KY2022-R193).
Results: The proband showed a markedly prolonged APTT (160.3 s) and significantly decreased FⅫ:C (2%) and FⅫ:Ag (5%) levels. Analysis of the F12 gene sequence revealed a 46C/T genotype in the promoter region, a heterozygous c.1457G>A (p.Cys467Tyr) missense variant in exon 12, and a heterozygous c.1561G>A (p.Glu502Lys) missense variant in exon 13. Bioinformatic analysis showed that the p.Cys467 is highly conserved across various species, and the p.Cys467Tyr variant may affect local structural stability of the FⅫ protein. The p.Cys467Tyr variant had no effect on the transcription of the F12 gene. However, the variant has significantly decreased the FⅫ:Ag levels and FⅫ protein expression in the cell culture supernatant compared to the wild-type expression vector, while in the cell lysate, it is higher than the wild-type expression vector. In other words, the p.Cys467Tyr variant has probably caused a secretion defect of FⅫ protein.
Conclusion: The 46C/T genotype, the heterozygous p.Cys467Tyr missense variant, and the heterozygous p.Glu502Lys missense variant are associated with reduced plasma FⅫ levels in this pedigree. The p.Cys467Tyr variant, which was unreported previously, did not affect the synthesis of FⅫ but may have resulted in a secretion defect.
Objective: To block the transmission of Cranio-facial-nasal syndrome (CFNS) caused by a large deletion of the EFNB1 gene through preimplantation genetic testing for monogenic disorders (PGT-M).
Methods: A patient with craniofacial deformities and his parents who had visited Shiyan People's Hospital in June 2020 were selected as the study subjects. The child underwent whole exome sequencing (WES) and qPCR validation. After genetic counseling, PGT-M was chosen for the reproductive blockage. This study was approved by the Ethics Committee of the Hospital (Ethics No.: sysrmyy-087).
Results: The child was diagnosed with CFNS due to a heterozygous deletion of exons 1-5 of the EFNB1 gene through WES and qPCR, which showed a X-linked dominant inheritance. The mother underwent ovarian stimulation with a modified PPOS protocol, which has yielded 11 oocytes. After ICSI fertilization, 4 blastocysts were formed, and MALBAC whole genome amplification was performed on the trophoblast biopsy cells, and SNP haplotypes of the family members and embryos were analyzed to indirectly determine the presence of maternal pathogenic haplotypes. Chromosomal copy number variation analysis was conducted through next-generation sequencing to screen for euploid embryos, resulting in the identification of two euploid embryos that did not carry the mutation of the EFNB1 gene. The first transfer was unsuccessful, but after adjusting the transfer timing through endometrial receptivity assessment (ERA), clinical pregnancy was achieved. Prenatal diagnosis at 19 weeks excluded the EFNB1 gene exons 1-5 deletion in the fetus. A healthy girl was delivered by Cesarean section at 38+6 weeks, and Q-PCR confirmed she has no aforementioned EFNB1 gene deletion.
Conclusion: This study has successfully blocked the transmission of CFNS caused by a large deletion of the EFNB1 gene (exons 1-5) using a PGT-M strategy, which may provide reference for the intervention of similar genomic variations that cannot be directly detected.
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.
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