After the promulgation of the first edition of expert consensus on the application of chromosomal microarray analysis (CMA) technology in prenatal diagnosis in 2014, after 8 years of clinical and technical development, CMA technology has become a first-line diagnosis technology for fetal chromosome copy number deletion or duplication abnormalities, and is widely used in the field of prenatal diagnosis in China. However, with the development of the industry and the accumulation of experience in case diagnosis, the application of CMA technology in many important aspects of prenatal diagnosis, such as clinical diagnosis testimony, data analysis and genetic counseling before and after testing, needs to be further standardized and improved, so as to make the application of CMA technology more in line with clinical needs. The revision of the guideline was led by the National Prenatal Diagnostic Technical Expert Group, and several prenatal diagnostic institutions such as Peking Union Medical College Hospital were commissioned to write, discuss and revise the first draft, which was discussed and reviewed by all the experts of the National Prenatal Diagnostic Technical Expert Group, and was finally formed after extensive review and revision. This guideline is aimed at the important aspects of the application of CMA technology in prenatal diagnosis and clinical diagnosis, from the clinical application of evidence, test quality control, data analysis and interpretation, diagnosis report writing, genetic counseling before and after testing and other work specifications are elaborated and introduced in detail. It fully reflects the integrated experience, professional thinking and guidance of the current Chinese expert team on the prenatal diagnosis application of CMA technology. The compilation of the guideline for the application of CMA technology in prenatal diagnosis will strive to promote the standardization and advancement of prenatal diagnosis of fetal chromosome diseases in China.
Female ; Humans ; Pregnancy ; Asian People ; Chromosome Aberrations ; Chromosome Deletion ; Chromosome Duplication/genetics* ; DNA Copy Number Variations/genetics* ; Fetal Diseases/genetics* ; Genetic Counseling ; Microarray Analysis ; Prenatal Care ; Prenatal Diagnosis ; Practice Guidelines as Topic

OBJECTIVE: To explore the incidence of azoospermia factor c (AZFc) microdeletion among patients with azoospermia or severe oligospermia, its association with sex hormone/chromosomal karyotype, and its effect on the outcome of pregnancy following intracytoplasmic sperm injection (ICSI) treatment. METHODS: A total of 1 364 males with azoospermia or severe oligospermia who presented at the Affiliated Maternity and Child Health Care Hospital of Jiaxing College between 2013 and 2020 were subjected to AZF microdeletion and chromosome karyotyping analysis. The level of reproductive hormones in patients with AZFc deletions was compared with those of control groups A (with normal sperm indices) and B (azoospermia or severe oligospermia without AZFc microdeletion). The outcome of pregnancies for the AZFc-ICSI couples was compared with that of the control groups in regard to fertilization rate, superior embryo rate and clinical pregnancy rate. RESULTS: A total of 51 patients were found to harbor AZFc microdeletion, which yielded a detection rate of 3.74%. Seven patients also had chromosomal aberrations. Compared with control group A, patients with AZFc deletion had higher levels of PRL, FSH and LH (P < 0.05), whilst compared with control group B, only the PRL and FSH were increased (P < 0.05). Twenty two AZFc couples underwent ICSI treatment, and no significant difference was found in the rate of superior embryos and clinical pregnancy between the AZFc-ICSI couples and the control group (P > 0.05). CONCLUSION The incidence of AZFc microdeletion was 3.74% among patients with azoospermia or severe oligospermia. AZFc microdeletion was associated with chromosomal aberrations and increased levels of PRL, FSH and LH, but did not affect the clinical pregnancy rate after ICSI treatment.
Child ; Humans ; Male ; Female ; Pregnancy ; Azoospermia/genetics* ; Oligospermia/genetics* ; Incidence ; Chromosome Deletion ; Chromosomes, Human, Y/genetics* ; Semen ; Infertility, Male/genetics* ; Chromosome Aberrations ; Follicle Stimulating Hormone/genetics*

OBJECTIVE: To explore the genetic etiology for a child featuring mental retardation, language delay and autism. METHODS: G-banding chromosomal karyotyping and single nucleotide polymorphism array (SNP-array) were carried out for the child and her parents. RESULTS: The child was found to have a 46,XX,dup(8p?) karyotype, for which both of her parents were normal. SNP-array revealed that the child has harbored a 6.8 Mb deletion in 8p23.3p23.1 and a 21.8 Mb duplication in 8p23.1p12, both of which were verified as de novo pathogenic copy number variants. CONCLUSION The clinical features of the child may be attributed to the 8p deletion and duplication. SNP-array can facilitate genetic diagnosis for children featuring mental retardation in conjunct with other developmental anomalies.
Humans ; Child ; Pregnancy ; Female ; Intellectual Disability/genetics* ; Prenatal Diagnosis ; Karyotyping ; Chromosome Banding ; Chromosome Deletion

OBJECTIVE: To explore the genetic basis for a fetus with club foot detected upon mid-pregnancy ultrasonography. METHODS: Amniotic fluid of the fetus and peripheral blood samples of its parents were collected and subjected to G-banding karyotype analysis and copy number variation sequencing (CNV-seq). The result was verified by fluorescence in situ hybridization (FISH). RESULTS: The fetus and its parents all had a normal karyotype. CNV-seq analysis revealed that the fetus has harbored a 23.12 Mb on chromosome 5 and a 21.46 Mb duplication on chromosome 7. FISH assay has verified that its mother has carried a cryptic t(5;7)(p14.3;q33) translocation. CONCLUSION CNV-seq combined with FISH can effectively detect cryptic chromosome aberrations, and can help to reduce severe birth defects and provide a basis for prenatal genetic counseling.
Pregnancy ; Female ; Humans ; Cri-du-Chat Syndrome ; In Situ Hybridization, Fluorescence ; DNA Copy Number Variations ; Prenatal Diagnosis ; Fetus ; Amniotic Fluid ; Chromosome Deletion

OBJECTIVE: To explore the genetic basis for a child with facial dysmorphism and multiple malformations. METHODS: The child, born at 34⁺⁶ weeks' gestation due to premature rupture of amniotic membrane, dichorionic diamniotic twinning and gestational diabetes, was subjected to chromosomal karyotyping analysis and copy number variations sequencing (CNV-seq). RESULTS: The child was found to have facial dysmorphism, hypospadia, cryptorchidism and hypotonia. He was found to have a 46,XY,del(3)(p26) karyotype in addition with a 9.80 Mb deletion (chr3: 60 000-9 860 000) encompassing 33 protein coding genes. CONCLUSION The 3p26.3p25.3 deletion probably underlay the multiple malformations in this child. Continuous follow-up is required to improve his quality of life.
Humans ; Male ; Chromosome Deletion ; DNA Copy Number Variations ; Quality of Life ; Abnormalities, Multiple/genetics* ; Phenotype

Spermatogenesis is regulated by several Y chromosome-specific genes located in a specific region of the long arm of the Y chromosome, the azoospermia factor region (AZF). AZF microdeletions are the main structural chromosomal abnormalities that cause male infertility. Assisted reproductive technology (ART) has been used to overcome natural fertilization barriers, allowing infertile couples to have children. However, these techniques increase the risk of vertical transmission of genetic defects. Despite widespread awareness of AZF microdeletions, the occurrence of de novo deletions and overexpression, as well as the expansion of AZF microdeletion vertical transmission, remains unknown. This review summarizes the mechanism of AZF microdeletion and the function of the candidate genes in the AZF region and their corresponding clinical phenotypes. Moreover, vertical transmission cases of AZF microdeletions, the impact of vertical inheritance on male fertility, and the prospective direction of research in this field are also outlined.
Humans ; Male ; Azoospermia/genetics* ; Sex Chromosome Aberrations ; Prospective Studies ; Chromosome Deletion ; Chromosomes, Human, Y/genetics* ; Infertility, Male/genetics* ; Sertoli Cell-Only Syndrome/genetics* ; Oligospermia/genetics*

OBJECTIVE: To explore the genetic basis for fetus with bilateral lateral ventriculomegaly. METHODS: Fetus umbilical cord blood and peripheral blood samples of its parents were collected. The fetus was subjected to chromosomal karyotyping, whilst the fetus and its parents were subjected to array comparative genomic hybridization (aCGH). The candidate copy number variation (CNV) were verified by qPCR, Application goldeneye DNA identification system was used to confirm the parental relationship. RESULTS: The fetus was found to have a normal karyotype. aCGH analysis indicated that it has carried a 1.16 Mb deletion at 17p13.3, which partially overlapped with the critical region of Miller-Dieker syndrome (MDS), in addition with a 1.33 Mb deletion at 17p12 region, which is associated with hereditary stress-susceptible peripheral neuropathy (HNPP). Its mother was also found to harbor the 1.33 Mb deletion at 17p12. qPCR analysis confirmed that the expression levels of genes from the 17p13.3 and 17p12 regions were about the half of that in the normal control, as well as the maternal peripheral blood sample. Parental relationship was confirmed between the fetus and its parents. Following genetic counseling, the parents has chosen to continue with the pregnancy. CONCLUSION The fetus was diagnosed with Miller-Dieker syndrome due to the de novo deletion at 17p13.3. Ventriculomegaly may be an important indicator for prenatal ultrasonography in fetuses with MDS.
Pregnancy ; Female ; Humans ; Classical Lissencephalies and Subcortical Band Heterotopias ; Comparative Genomic Hybridization ; DNA Copy Number Variations ; Fetus ; Hydrocephalus ; Prenatal Diagnosis ; Chromosome Deletion

OBJECTIVE: To explore the genetic basis for a Chinese pedigree with 6q26q27 microduplication and 15q26.3 microdeletion. METHODS: A fetus with a 6q26q27 microduplication and a 15q26.3 microdeletion diagnosed at the First Affiliated Hospital of Wenzhou Medical University in January 2021 and members of its pedigree were selected as the study subject. Clinical data of the fetus was collected. The fetus and its parents were analyzed by G-banding karyotyping and chromosomal microarray analysis (CMA), and its maternal grandparents were also subjected to G-banding karyotype analysis. RESULTS: Prenatal ultrasound had indicated intrauterine growth retardation of the fetus, though no karyotypic abnormality was found with the amniotic fluid sample and blood samples from its pedigree members. CMA revealed that the fetus has carried a 6.6 Mb microduplication in 6q26q27 and a 1.9 Mb microdeletion in 15q26.3, and his mother also carried a 6.49 duplication and a 1.867 deletion in the same region. No anomaly was found with its father. CONCLUSION The 6q26q27 microduplication and 15q26.3 microdeletion probably underlay the intrauterine growth retardation in this fetus.
Female ; Humans ; Pregnancy ; East Asian People ; Fetal Growth Retardation/genetics* ; Karyotype ; Pedigree ; Prenatal Diagnosis ; Sequence Deletion ; Chromosome Duplication

OBJECTIVE: To explore the clinical phenotype and genetic characteristics of a fetus with 17q12 microdeletion syndrome. METHODS: A fetus with 17q12 microdeletion syndrome who was diagnosed at Huzhou Maternal & Child Health Care Hospital in June 2020 was selected as the study subject. Clinical data of the fetus was collected. The fetus was subjected to chromosomal karyotyping and chromosomal microarray analysis (CMA). To determine the origin of fetal chromosomal abnormality, its parents were also subjected to CMA assay. The postnatal phenotype of the fetus was also investigated. RESULTS: Prenatal ultrasound revealed polyhydramnios and fetal renal dysplasia. The fetus was found to have a normal chromosomal karyotype. CMA has detected a 1.9 Mb deletion in the 17q12 region, which has encompassed five OMIM genes including HNF1B, ACACA, ZNHIT3, CCL3L1 and PIGW. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the 17q12 microdeletion was predicted as pathogenic copy number variation (CNV). CMA analysis has detected no pathogenic CNV in both parents. After birth, the child was found to have renal cysts and abnormal brain structure. Combined with the prenatal findings, the child was diagnosed with 17q12 microdeletion syndrome. CONCLUSION The fetus has 17q12 microdeletion syndrome presenting as abnormalities of the kidney and central nervous system, which are strongly correlated with functional defects of the deletion region involving the HNF1B and other pathogenic genes.
Female ; Pregnancy ; Humans ; Chromosome Deletion ; DNA Copy Number Variations ; Chromosome Disorders/genetics* ; Kidney ; Fetus ; Microarray Analysis ; Prenatal Diagnosis

OBJECTIVE: To explore the clinical and genetic characteristics of two children with Williams-Beuren syndrome (WBS). METHODS: Two children who had presented at the Department of Pediatrics, General Hospital of Ningxia Medical University respectively on January 26 and March 18, 2021 were selected as the study subjects. Clinical data and results of genetic testing of the two patients were analyzed. RESULTS: Both children had featured developmental delay, characteristic facies and cardiovascular malformation. Child 1 also had subclinical hypothyroidism, whilst child 2 had occurrence of epilepsy. Genetic testing revealed that child 1 has harbored a 1.54 Mb deletion in the 7q11.23 region, whilst child 2 has a 1.53 Mb deletion in the same region, in addition with a c.158G>A variant of the ATP1A1 gene and a c.12181A>G variant of the KMT2C gene. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.158G>A and c.12181A>G variants were rated as variants of unknown significance (PM1+PM2_Supporting+PP2+PP3；PM2_Supporting). CONCLUSION Both children had characteristic features of WBS, for which deletions of the 7q11.23 region may be accountable. For children manifesting developmental delay, facial dysmorphism and cardiovascular malformations, the diagnosis of WBS should be suspected, and genetic testing should be recommended to confirm the diagnosis.
Child ; Humans ; Williams Syndrome/diagnosis* ; Genetic Testing ; Facies ; Epilepsy/genetics* ; Chromosomes, Human, Pair 7/genetics* ; Chromosome Deletion