1.Prenatal diagnosis of a fetus with Rubinstein-Taybi syndrome
Jia PENG ; Bo YANG ; Handuo WANG ; Zhiying ZHANG ; Fangying CUI ; Haiyu LI ; Yueshu ZHAO ; Ling LIU
Chinese Journal of Medical Genetics 2024;41(8):973-976
Objective:To explore the clinical characteristics and variant of CREBBP gene in a fetus with Rubinstein-Taybi syndrome (RSTS). Methods:A fetus with RSTS diagnosed at the Third Affiliated Hospital of Zhengzhou University in August 2022 was selected as the study subject. Clinical data, amniotic fluid sample of the fetus and peripheral blood samples of its parents were collected for whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing.Results:Foot malformation, cerebellar vermis agenesis, brain agenesis, polysyndactyly of the big toes and other phenotypes were found by prenatal ultrasound. WES revealed that the fetus has harbored a heterozygous c. 4684G>T (p.E1562*) variant in exon 28 of the CREBBP gene (NM_004380.3), which was de novo in origin. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was predicted to be pathogenic (PVS1+ PS2_Moderate+ PM2_Supporting). After genetic counseling, the couple had opted to terminate the pregnancy and refused autopsy for the fetus. Conclusion:The c. 4684G>T (p.E1562*) variant of the CREBBP gene probably underlay the RSTS in this fetus. The newly discovered variant has enriched the mutational spectrum of the CREBBP gene and illustrated that WES is an efficient tool for the prenatal diagnosis of RSTS.
2.Genetic analysis of a child with mos 46, X, psu idic(X)(q21.3)40/45, X3
Ting YIN ; Fang ZHANG ; Xinxin TANG ; Minmin ZHU ; Anshun ZHENG ; Qin ZHENG ; Xiaoxi WANG ; Leilei WANG
Chinese Journal of Medical Genetics 2024;41(8):977-981
Objective:To explore the correlation between structural chromosomal abnormality and clinical characteristics of a child featuring gonadal dysplasia.Methods:A 13-year-old child who was admitted to Lianyungang Maternal and Child Health Care Hospital on February 7, 2023 for primary amenorrhoea and occasional abdominal pain was selected as the study subject. Clinical data of the child was collected, and peripheral blood samples of the child and her parents were collected. G-banding chromosomal karyotyping and copy number variation sequencing (CNV-seq) were carried out. "Pseudodual centromere isochromosome X" and "psu idic(X)" were used as keywords to search the CNKI, Wanfang and PubMed databases, and the search period was set as from January 1, 2002 to June 1, 2023. Relevant literature on the structural abnormality of X chromosome was searched and analyzed retrospectively.Results:The child has a height of 153 cm and weighed 45 kg. She has no obvious facial dysmorphism. Laboratory tests showed that she had higher FSH and luteinizing hormone, and lower E2. Ultrasonography showed that she had small ovaries and rudimentary uterus. She was found to have a karyotype of 46, X, psu idic(X)(q21.3)[40]/mos 45, X[3], whilst both of her parents had a normal karyotype. CNV-seq showed that she had a 63.27 Mb deletion in Xq21.32q28 and a 91.59 Mb duplication in Xp22.33q21.32 (mosaicism rate = 74%). A total of 11 relevant literature were retrieved. Clinical phenotypes of patients with similar structural chromosomal abnormalities were diverse, which was closely related to the mosaicism rate of the 45, X karyotype and the location of the breaking point.Conclusion:46, X, psu idic(X)(q21.3)/45, X probably underlay the dysplasia of uterus and ovary and sex hormone abnormalities in this child, while her height was spared. Deletion of Xq21.32q28 is a key factor leading to Turner syndrome-like phenotype such as rudimentary uterus and ovarian dysplasia.
3.Molecular biological identification of a case with A223B subtype
Li WANG ; Qiankun YANG ; Shuya WANG ; Ying XIE ; Xue LIU ; Yanli CHANG ; Yongkui KONG
Chinese Journal of Medical Genetics 2024;41(8):982-987
Objective:To study the molecular basis for a proband with A subtype B of the ABO blood group and explore the influence of amino acid variant on the activity of glycosyltransferase (GT).Methods:A proband who had presented at the First Affiliated Hospital of Zhengzhou University on July 2, 2020 was selected as the study subject. Serological identification of the ABO blood groups of the proband and her family members were performed by gel card and test tube methods. The ABO gene of the proband was identified by PCR-sequence specific primers (PCR-SSP) and DNA sequencing. A 3D molecular homologous model was constructed to predict the impact of the variant on the stability of α-(1→3)-D-N-acetylgalactosamine transferase (GTA). Results:The red blood cells of the proband, her mother and two younger brothers showed weak agglutination with anti-A and strong agglutination with anti-B. The sera showed 1~2+ agglutination with Ac and no agglutination with Bc. Based on the serological characteristics, the proband was identified as AwB subtype. Pedigree analysis suggested that the variant was inherited from her mother. The blood group of the proband was identified as A223B type by PCR-SSP. ABO gene sequencing analysis showed that the proband has harbored heterozygous variants of c. 297A>G, c. 467C>T, c. 526C>G, c. 657C>T, c. 703G>A, c. 796C>A, c. 803G>C, c. 930G>A and c. 1055insA. Based on the results of clone sequencing, it was speculated that the genotype was ABO* A223/ ABO* B.01. There were c. 467C>T and c. 1055insA variants compared with ABO* A1.01, and c. 1055insA variant compared with ABO* A1.02. Homologous modeling showed that the C-terminal of A223 GT was significantly prolonged, and the local amino acids and hydrogen bond network have changed. Conclusion:Above results revealed the molecular genetics mechanism of A223B subtype. The c. 1055insA variant carried by the proband may affect the enzymatic activity of GTA and ultimately lead to weakening of A antigen.
4.Association of CTLA-4 gene polymorphisms with the genetic susceptibility and prognosis of patients with Bladder urothelial carcinoma
Junpeng LI ; Lin ZHANG ; Haifeng XIE ; Yukun GE ; Lei WANG
Chinese Journal of Medical Genetics 2024;41(8):988-993
Objective:To assess the association of cytotoxic T lymphocyte-associated antigen-4 ( CTLA-4) gene polymorphisms with the prognosis of patients with Bladder urothelial carcinoma (BUC). Methods:From February 2019 to October 2020, 256 BUS patients treated at the Xinxiang Central Hospital were selected as the study group, whilst 250 healthy individuals were selected as the control group. Genotypes of rs5742909 (-318C/T), rs231775 (+ 49A/G) and rs4553808 (-1661A/G) were determined by PCR-restriction fragment length polymorphism assay. The frequencies of genotypes and alleles of the CTLA-4 gene were compared between the two groups. All patients had undergone surgical treatment and were followed up for 3 years and divided into good prognosis group ( n=166) and poor prognosis group ( n=86) based on the status of disease. The distribution of alleles and genotypes were compared, and Kaplan-Meier analysis was used to assess the association of genetic polymorphisms with the prognosis. Results:No significant difference was found in the gender, age, BMI, smoking history and alcohol use between the two groups ( P>0.05). The frequencies of GG genotype and G allele for the rs231775 (+ 49A/G) and rs4553808 (-1661A/G) loci were significantly higher in the study group compared with the control group ( P<0.05), whilst no statistical difference was found in the genotypic and allelic frequency for the rs5742909 locus between the two groups ( P>0.05). Among the 252 subjects who had completed follow-up, 86 had poor prognosis and 166 had good prognosis. The frequencies of GG genotype and G allele at the rs231775 (+ 49A/G) and rs4553808 (-1661A/G) loci were significantly lower in the good prognosis group compared with the poor prognosis group ( P<0.05). Kaplan-Meier survival curve analysis showed that the survival time of patients with GG genotype for the rs231775 (+ 49A/G) and rs4553808 (-1661A/G) loci was significantly shorter than patients with AA or AG genotypes (Log Rank 2 = 13.654, 9.974, P<0.001). Conclusion:The polymorphisms of the rs231775 and rs4553808 loci of the CTLA-4 gene are associated with genetic susceptibility and poor prognosis for BUC, and a higher GG genotypic frequency may increase the risk for infection and poor prognosis of the patients.
5.Advance of research on 22q11.2 deletion syndrome
Chinese Journal of Medical Genetics 2024;41(8):994-1000
22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion disorder. Its phenotype is highly variable with incomplete penetrance. 22q11.2DS is a rare disease, and the research progress is relatively slow, which has restricted its treatment and intervention. In recent years, much progress has been made in the pathogenic mechanism and genome-wide association study of 22q11.2DS. In this review, the pathogenesis of 22q11.2DS was summarized. Thereafter, the molecular and pathological mechanisms of TBX1 and DGCR8 genes were clarified. Finally, factors affecting the penetrance of cardiac and immune system phenotypes were reviewed. This review may enhance the understanding of 22q11.2DS and has important clinical implications on the prenatal diagnosis, genetic counseling, treatment and intervention of this disease.
6.Advances in genetic research on Non-syndromic congenital joint synostosis
Mei DENG ; Fang SHEN ; Yongjia YANG
Chinese Journal of Medical Genetics 2024;41(8):1001-1009
Congenital joint synostosis (CJS) is a functional impairment resulting from failure in joint morphogenesis during embryonic development. Clinically, it may be classified as syndromic (sCJS) and non-syndromic (nsCJS) disorders. Common sCJS include chromosomal disorders such as Klinefelter syndrome and single-gene disorders like Apert/Pfeiffer/Crouzon syndromes, Holt-Oram syndrome, Ehlers-Danlos syndrome, and Radial-ulnar synostosis with thrombocytopenia, presenting with multiple system/organ anomalies. By contrast, nsCJS manifest with only joint abnormalities, affecting one or multiple joints. This review has focused on human nsCJS and its genetic etiology. To date, variants in seven genes ( NOG, GDF5, FGF9, GDF6, FGF16, SMAD6, and MECOM) have been identified as causative factors for nsCJS. This review has focused on such genes and provided a comprehensive review for the clinical phenotypes, genetic patterns, common variants, and underlying mechanisms associated with nsCJS based on a literature review. In addition, it has also analyzed other candidate genes for nsCJS within the context of relevant signaling pathways involved in joint morphogenesis.
7.Research progress on DNMT3A gene expression in Acute myeloid leukemia
Jiawei ZHOU ; Tao WU ; Wenhui LIU
Chinese Journal of Medical Genetics 2024;41(8):1010-1015
DNA methylation is an important epigenetic regulatory mechanism which plays a crucial role in cell differentiation and development. Its function is closely related to DNA methyltransferase 3 alpha (DNMT3A), which can affect gene expression and stem cell differentiation. The mutation rate of the DNMT3A gene is relatively high in Acute myeloid leukemia (AML), but its type and pathogenic mechanism are not yet clear. Further research on DNMT3A may help to identify its pathogenic targets and provide a basis for precise treatment of AML. This article has provided a review for the research progress on the expression of the DNMT3A gene in AML.
8.Expert consensus on the clinical application of efficient intelligent chromosomal karyotyping precise auxiliary diagnosis system
Hao WANG ; Juan WEN ; Yi LAI ; Lingqian WU
Chinese Journal of Medical Genetics 2024;41(9):1025-1031
Chromosomal karyotyping analysis has been considered as the gold standard for cytogenetic diagnosis and an effective measure for preventing birth defects. However, conventional karyotyping analysis relies heavily on manual recognition, which is time-consuming and labor-intensive. The application of an efficient intelligent chromosomal karyotyping precise auxiliary diagnosis system in clinical practice can significantly reduce the analysis time and greatly improve the efficiency, increase the detection rate for low-percentage mosaicisms, and promote homogenization between laboratories. This can effectively enhance the capacity and level of cytogenetic diagnosis. With the continuous application of such system in the field of karyotyping analysis, a substantial amount of clinical application data and experience has been accumulated. This consensus has been formulated after multiple rounds of discussion by experts from the clinical application collaboration group of the efficient intelligent chromosomal karyotyping precise auxiliary diagnosis system. It aims to provide a reference for peers to better utilize intelligent auxiliary diagnosis systems during chromosomal karyotyping analysis and promote the standardized development of karyotyping analysis technology.
9.Progress in fetal fraction prediction of placental diseases
Shanshan LI ; Wen LI ; Zhuo WEI ; Yongmei SHEN ; Xiaomin ZHAO ; Liying YAO ; Ying CHANG
Chinese Journal of Medical Genetics 2024;41(9):1032-1038
Placental diseases may affect the outcome of pregnancy and long-term health of the mother and fetus. Fetal fraction is a key indicator for the success of non-invasive prenatal testing, and has been associated with gestational age, body mass index and fetal chromosomal aneuploidies. Many studies have found that fetal fraction is also related to placenta-derived diseases and may become a new predictor for such diseases. This article has summarized the association between the two, with an aim to provide new ideas for the prediction of placental diseases.
10.Molecular study of a case with variant of RHCE*ce allele in haplotype dce resulting in weakened e antigen
Yongkui KONG ; Hecai YANG ; Ming SHAO ; Yinghui CHEN-LI ; Wanjin ZHANG ; Xiaoyan ZHANG ; Jing WANG ; Xianping LYU ; Qiankun YANG
Chinese Journal of Medical Genetics 2024;41(9):1039-1044
Objective:To explore the RH genotype for a female with RhD(-) blood type and its molecular basis. Methods:A 26-year-old female who had attended the outpatient clinic of the First Affiliated Hospital of Zhengzhou University in August 2019 was selected as the study subject. Peripheral blood samples were collected from the proband and her parents for Rh phenotyping with gel card method. PCR-sequence-based typing (PCR-SBT) and DNA sequencing were used to determine the RHD zygosity and RH genotype of the proband and her parents. Homology modeling of Rh proteins was performed with bioinformatic software, and protein structural alterations caused by the variant was simulated by molecular dynamics. This study was approved by the Medical Ethics Committee of the First Affiliated Hospital of Zhengzhou University (Ethics No. 2023-KY-0870-003). Results:Serological tests showed that the proband and her father both had weakened e antigen of the Rh phenotype. PCR-SBT and DNA sequencing showed that the genotypes of the proband and her parents were dce/ dCE, dce/ DcE and dCE/ DcE, respectively. And the genotypes of the RHD and RHCE of the proband were RHD*01N.01/ RHD*01N.16, RHCE*01.01/RHCE*04, respectively. Protein simulation and molecular dynamics analysis revealed that the ce_16C variant resulted from RHCE* ce (c.48G>C) may alter the structure of intracellular and extracellular loops, mainly affecting the mobility of extracellular loops 2, 6 and intracellular loops 3, 4. Conclusion:Variant of the RHCE* ce allele c. 48G>C probably underlay the weakened e antigen in this proband.

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