OBJECTIVE: To assess the carrier frequency of spinal muscular atrophy (SMA) in women of childbearing age in Chongqing and to evaluate prenatal diagnostic outcomes in high-risk couples. METHODS: A total of 17 926 women of childbearing age attending Chongqing Health Center for Women and Children between May 2021 and November 2023 were enrolled, including 3 398 pre-pregnant women and 14 528 pregnant women, all of whom had no clinical phenotype or family history of SMA or related neuromuscular disorders. Real-time quantitative PCR (RT-qPCR) was used to determine the copy number variations in exons 7 and 8 (E7, E8) of the SMN1 gene. High-risk carriers were identified based on the genetic screening results. Multiplex ligation-dependent probe amplification (MLPA) was employed for prenatal diagnosis of fetuses from high-risk couples. This study was approved by the Medical Ethics Committee of Chongqing Health Center for Women and Children (Ethics No.2021-RGI-02). RESULTS: Among the 17 926 women of childbearing age, 298 (1.66%) were identified as heterozygous carriers, including 278 (1.55%) with concurrent deletions of E7 and E8, and 20 (0.11%) with isolated deletions of E7. Seven high-risk couples were identified, six of whom were prenatal couples. Of the two fetuses from these high-risk pregnancies, both exhibited heterozygous deletions of E7 and E8 in the SMN1 gene, while four fetuses showed no abnormalities. CONCLUSION This study provides a comprehensive assessment of the carrier frequency of SMA among women of childbearing age in Chongqing, offering valuable data for the primary and secondary prevention of SMA-related birth defects in the region.
Humans ; Female ; Muscular Atrophy, Spinal/diagnosis* ; Pregnancy ; Prenatal Diagnosis/methods* ; Adult ; Survival of Motor Neuron 1 Protein/genetics* ; Genetic Carrier Screening/methods* ; DNA Copy Number Variations/genetics* ; China ; Genetic Testing ; Heterozygote

OBJECTIVE: To assess the value of genetic screening by high-throughput sequencing (HTS) for the early diagnosis of neonatal diseases. METHODS: A total of 2 060 neonates born at Ningbo Women and Children's Hospital from March to September 2021 were selected as the study subjects. All neonates had undergone conventional tandem mass spectrometry metabolite analysis and fluorescent immunoassay analysis. HTS was carried out to detect the definite pathogenic variant sites with high-frequency of 135 disease-related genes. Candidate variants were verified by Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). RESULTS: Among the 2 060 newborns, 31 were diagnosed with genetic diseases, 557 were found to be carriers, and 1 472 were negative. Among the 31 neonates, 5 had G6PD, 19 had hereditary non-syndromic deafness due to variants of GJB2, GJB3 and MT-RNR1 genes, 2 had PAH gene variants, 1 had GAA gene variants, 1 had SMN1 gene variants, 2 had MTTL1 gene variants, and 1 had GH1 gene variants. Clinically, 1 child had Spinal muscular atrophy (SMA), 1 had Glycogen storage disease II, 2 had congenital deafness, and 5 had G6PD deficiency. One mother was diagnosed with SMA. No patient was detected by conventional tandem mass spectrometry. Conventional fluorescence immunoassay had revealed 5 cases of G6PD deficiency (all positive by genetic screening) and 2 cases of hypothyroidism (identified as carriers). The most common variants identified in this region have involved DUOX2 (3.93%), ATP7B (2.48%), SLC26A4 (2.38%), GJB2 (2.33%), PAH (2.09%) and SLC22A5 genes (2.09%). CONCLUSION Neonatal genetic screening has a wide range of detection and high detection rate, which can significantly improve the efficacy of newborn screening when combined with conventional screening and facilitate secondary prevention for the affected children, diagnosis of family members and genetic counseling for the carriers.
Child ; Infant, Newborn ; Humans ; Female ; Prospective Studies ; Connexins/genetics* ; Connexin 26/genetics* ; Glucosephosphate Dehydrogenase Deficiency ; Mutation ; Sulfate Transporters/genetics* ; DNA Mutational Analysis ; Genetic Testing/methods* ; Deafness/genetics* ; Neonatal Screening/methods* ; Hearing Loss, Sensorineural/genetics* ; High-Throughput Nucleotide Sequencing ; Solute Carrier Family 22 Member 5/genetics*

Child, Preschool ; Flow Cytometry ; methods ; Genetic Carrier Screening ; Granulomatous Disease, Chronic ; diagnosis ; genetics ; Humans ; Infant ; Male

OBJECTIVETo explore the frequencies of heterozygosity in X-linked G6PD, P55, BTK, and FHL-1 gene exonic polymorphic loci among Chinese females and the value of determination of hematopoietic clonality by detection of these X-chromosome exonic polymorphisms based on X-chromosome inactivation patterns (XCIP)-transcription-based clonality assays (TCA).

METHODSGenomic DNA was extracted from peripheral blood of 446 Chinese healthy females. Allele-specific PCR (ASPCR) or PCR-restriction enzyme digestion method was applied for detecting G6PD, P55, BTK and FHL-1 polymorphisms. Those heterozygotic loci were used as markers to examine the hematopoietic clonality of bone marrow mononuclear cells by TCA from essential thrombocythemia (ET) patients with JAK2V617F mutation and myelodysplastic syndrome (MDS) patients with abnormal karyotype.

RESULTSAmong the total 446 genomic DNA samples, the frequencies of heterozygosity in G6PD, P55, BTK and FHL-1 loci were 12.8%, 29.4%, 52.0% and 46.4%, respectively. About 81.4% of females were heterozygous at one or more loci. All 10 ET patients with JAK2V617F mutation and 2 MDS patients with abnormal karyotype, which were heterozygotic in either locus, had monoclonal/oligoclonal hematopoiesis.

CONCLUSIONClonality detection based on X chromosome inactivation patterns-transcription based clonality assays is applicable to about 80% of Chinese females.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Alleles ; Asian Continental Ancestry Group ; genetics ; Chromosomes, Human, X ; Exons ; Female ; Genes, X-Linked ; Genetic Carrier Screening ; Genetic Linkage ; Glucosephosphate Dehydrogenase ; genetics ; Hematopoiesis ; genetics ; Humans ; Middle Aged ; Polymerase Chain Reaction ; methods ; Polymorphism, Single Nucleotide ; X Chromosome Inactivation ; Young Adult

OBJECTIVETo study the application of the multiplex ligation-dependent probe amplification (MLPA) method in genetic and prenatal diagnosis for spinal muscular atrophy (SMA).

METHODSFour patients, 16 parents and 4 fetuses from 8 SMA pedigrees were included. MLPA was performed for molecular analysis, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for the mutation detection of the 4 patients.

RESULTSFor all the four patients, the same homozygous deletion of the exons 7 and 8 of the survival motor neuron 1 (SMN1) gene, was detected by PCR-RFLP and MLPA. All fourteen parents from the 8 pedigrees were carriers of the SMN1 gene heterozygous deletion, except the mothers in pedigrees 1 and 4 in whom the mutations were different.

CONCLUSIONMLPA is a simple and efficient quantitative method for copy number analysis of the SMN genes. It can be used for the genetic diagnosis and prenatal diagnosis of the SMA patients and carriers.

Adult ; Amplified Fragment Length Polymorphism Analysis ; Exons ; Female ; Genetic Carrier Screening ; Heterozygote ; Humans ; Ligase Chain Reaction ; methods ; Male ; Muscular Atrophy, Spinal ; diagnosis ; genetics ; Pedigree ; Polymorphism, Restriction Fragment Length ; Pregnancy ; Prenatal Diagnosis ; methods ; Sequence Deletion ; Survival of Motor Neuron 1 Protein ; genetics ; Young Adult

INTRODUCTIONWe report the fi rst successful preimplantation genetic diagnosis (PGD) for Hb Bart's hydrops fetalis in Singapore, involving both fresh and frozen embryo replacement cycles.

CLINICAL PICTURETwo couples who were carriers of the Southeast Asian type double gene deletion (--(SEA) deletion carriers) requested for PGD. Couple A had 2 previous affected pregnancies, while couple B have a child of unknown genotypic status.

TREATMENTOne PGD cycle was performed for each couple. The --(SEA) deletion was detected using a gap-PCR strategy. Couple A had 1 fresh-embryo replacement cycle while couple B underwent 2 frozen-embryo replacement cycles.

OUTCOMECouple A achieved a twin pregnancy. Second trimester complications resulted in premature delivery, where 1 baby girl survived. Couple B achieved a singleton pregnancy resulting in delivery of a healthy baby boy. Genotype analysis of all babies confirmed the PGD results consistent with clinically unaffected status.

CONCLUSIONSWe have successfully performed PGD to avoid Hb Bart's hydrops fetalis syndrome.

Adult ; Embryo Transfer ; Female ; Genetic Carrier Screening ; Genetic Testing ; Hemoglobins, Abnormal ; Humans ; Hydrops Fetalis ; diagnosis ; genetics ; prevention & control ; Male ; Minisatellite Repeats ; genetics ; Ovulation Induction ; methods ; Polymerase Chain Reaction ; Pregnancy ; Pregnancy Complications, Hematologic ; diagnosis ; genetics ; prevention & control ; Preimplantation Diagnosis ; Singapore ; Sperm Injections, Intracytoplasmic ; alpha-Globins ; genetics

OBJECTIVEDystrophin gene deletion junction is the unique DNA sequence resulted from illegitimate recombination after the gene deletion. A novel accurate approach is presented here for the detection of deletional pseudohypertrophic muscular dystrophy carriers with the deletion junctions.

METHODSA Becker muscular dystrophy (BMD) family from Zhaoqing, Guangdong, China was used. Two males in the family were diagnosed as BMD patients, 3 phenotypically normal females and 1 chorionic villi sample of an artificial abortion were waiting for diagnosis. The index patient was identified as exons 3-5 deletion of the dystrophin gene. Then a PCR-based genome-walking method was used to locate the breakpoints in corresponding introns. Finally, deletion junctions of the 6 family members were amplified by PCR with primers adjacent to breakpoints and sequenced.

RESULTSThe deletion junctions of all patients and carriers of the BMD family were cloned and sequenced. The 3 females and 1 chorionic tissue were diagnosed as female carriers.

CONCLUSIONIn this study researchers have successfully carried out accurate gene diagnosis of deletional pseudohypertrophic carriers by cloning and sequencing the deletion junctions, and explored the prospect of using deletion junctions in prenatal diagnosis of BMD.

Base Sequence ; Cloning, Molecular ; DNA Mutational Analysis ; Female ; Gene Deletion ; Genetic Carrier Screening ; methods ; Humans ; Male ; Molecular Sequence Data ; Muscular Dystrophy, Duchenne ; diagnosis ; genetics ; Pedigree ; Polymerase Chain Reaction ; methods ; Pregnancy ; Prenatal Diagnosis ; Recombination, Genetic

OBJECTIVESpinal muscular atrophy (SMA) is one of common autosomal recessive diseases and is characterized by degeneration of the anterior horn cells of the spinal cord. The reported prevalence is 1/10,000 live births with a carrier rate of one in 50. It is important in genetic counseling to identify the carriers with one copy deletion for the survival motor neuron (SMN(1)) gene. However, the duplication of the SMA locus makes the detection of SMA carriers difficult. This study aimed to determine the potential of the quantitative PCR analysis in the identification of SMA carriers.

METHODSThe SMN(1) gene copy number was detected by realdouble ended arrowtime PCR with TaqMan technology in 109 SMA parents of affected children and 40 normal controls.

RESULTSThe average copy numbers of SMN(1) in the individuals with known one copy of the SMN(1) gene and with the two copies were 0.777 +/-0.035 (CV=4.5%) and 2.064 +/-0.120 (CV= 5.8%) respectively. The average copy number of SMN(1) in all of the parents with affected individuals was 0.798 +/-0.108 (CV=13.5%), and that of normal controls was 2.106 +/-0.18 (CV=8.5%). About 98% of SMA patients' parents carried 1 copy SMN(1), and 95% of normal controls carried 2 copies.

CONCLUSIONSThe gene copy numbers for SMN(1) were one and two for SMA carriers and non-carriers, respectively. Our results suggested that the quantitative PCR analysis can distinguish the SMN(1) deletion carriers from non-carriers.

Cyclic AMP Response Element-Binding Protein ; genetics ; Female ; Gene Dosage ; Genetic Carrier Screening ; methods ; Humans ; Male ; Muscular Atrophy, Spinal ; genetics ; Nerve Tissue Proteins ; genetics ; Polymerase Chain Reaction ; methods ; RNA-Binding Proteins ; genetics ; Regression Analysis ; SMN Complex Proteins

This study was aimed to investigate the prevalence and genotype distribution of heterozygotes in beta-thalassemia combining deletional alpha-thalassemia by using molecular detection and haematological methods. Three common deletions of alpha-thalassemia were detected by using gap-PCR. The mutations of beta-thalassemia were identified by using PCR with reverse dot blot hybridization. The routine analysis of blood cells was carried out. The results indicated that 15 cases from the 81 beta-thalassemia traits were found to be the compound heterozygosity for beta-thalassemia and alpha-thalassemia with 9 different types of gene defects with 18.52% detection rate. There were 6 cases (7.41%) of beta-thalassemia heterozygote combining alpha-thalassemia-1 gene (--(SEA)/alphaalpha), 8 cases (9.88%) combining with alpha-thalassemia-2 gene including 6 (7.41%) right ward deletion (-alpha(3.7)/alphaalpha) and 2 (2.47%) left ward deletion (-alpha(4.2)/alphaalpha), and 1 case (1.23%) combining deletional HbH gene (--(SEA)/-alpha(3.7)). No significant differences were found between beta-thalassemia heterozygotes combining deletional alpha-thalassemia and pure beta-thalassemia in all RBC parameters. It is concluded that the incidence of beta-thalassemia heterozygotes combining with deletional alpha-thalassemia is frequent in Wuzhou city. The hematological analysis can not give specificity for diagnosing these dual heterozygotes. Gap-PCR as a routine method for thalassemia screening has the advantages in reducing the possibility of failing to detect the combining heterozygosity for beta-thalassemia and alpha-thalassemia. It is more useful for genetic counselling and prenatal diagnosis of this disease.
Adolescent ; Adult ; Female ; Gene Deletion ; Genetic Carrier Screening ; methods ; Genotype ; Heterozygote ; Humans ; Male ; alpha-Thalassemia ; genetics ; beta-Thalassemia ; genetics

OBJECTIVETo gain a primary understanding of the prevalence of 21-hydroxylase deficiency(21-OHD) heterozygote (carrier) among androgen excess women of Chinese Han nationality, compare the molecular genetic changes therein revealed with the results of adrenocorticotropic hormone (ACTH) stimulating test, and assess the carriers' phenotype-genotype correlation.

METHODSEighty-two androgen excess cases and 14 healthy women underwent ACTH stimulating test during the follicular phase. Molecular genetic analysis of CYP21 for 9 common mutations was performed with the method of amplification-created restriction sites.

RESULTSIn androgen excess group, the basal level of F0 (P<0.01), as well as basal 17-OHP0 and the ACTH stimulated concentrations of 17-OHP60 were much higher than controls (P<0.01), and there was no obvious discrepancy in F60 (P>0.05). The net increase of 17-OHP and the ratio of net increase of 17-OHP to net increase of F were also higher than controls (P<0.01). No CYP21 gene mutations were found in control group. Four patients of the androgen excess group were identified as heterozygous carriers of CYP21 mutations. The ACTH stimulating test results from gene normal patients and from carriers overlapped to a certain extent.

CONCLUSIONAmong 82 patients of Chinese Han nationality androgen excess women, 4.9% were 21-OHD heterozygous. The response of serum 17-OHP is not useful for predicting CYP21 gene mutation carrier status. Genotyping is the most reliable method to detect carrier.

Adolescent ; Adrenal Hyperplasia, Congenital ; diagnosis ; ethnology ; genetics ; Adrenocorticotropic Hormone ; Adult ; Asian Continental Ancestry Group ; genetics ; Child ; China ; Female ; Genetic Carrier Screening ; methods ; Genotype ; Humans ; Mutation ; Polymerase Chain Reaction ; Steroid 21-Hydroxylase ; genetics ; metabolism