Dystrophinopathies caused by variants of DMD gene are a group of muscular diseases including Duchenne muscular dystrophy, Becker muscular dystrophy, and DMD-associated dilated cardiomyopathy. With the advancement of genetic testing techniques and wider implementation of genetic screening, especially the expanded carrier screening, more and more individuals carrying DMD gene variants have been identified, whereas the genetic counseling capacity is relatively insufficient. Currently there is still a lack of professional norms for genetic counseling on dystrophinopathies. In this consensus, the main points to be covered in the pre- and post-test consultation have been discussed, with an aim to provide genetic counseling guidance for the disease diagnosis, treatment, and family reproduction.

OBJECTIVE: To identify the pathogenic variant for a husband with osteogenesis imperfecta and provide preimplantation genetic testing (PGT) for the couple. METHODS: High-throughput sequencing and Sanger sequencing were carried out to identify the pathologic variant in the husband patients. PGT of embryos was performed through direct detection of the mutation site. Meanwhile, chromosome aneuploidy of the blastocysts was screened. Following transplantation, cytogenetic and genetic testing of fetal amniotic fluid sample was carried out during mid-pregnancy. Chromosome copy number variant (CNV) was detected at multiple sites of the placenta after delivery. RESULTS: The husband was found to harbor heterozygous c.544-2A>G variant of the COL1A1 gene. The same variant was not detected in either of his parents. PGT revealed that out of three embryos of the couple, one was wild-type for the c.544-2A site but mosaicism for duplication of 16p13.3.11.2. The other two embryos were both heterozygous for the c.544-2A>G variant. Following adequate genetic counseling, the wild-type embryo was transplanted. Amniotic fluid testing confirmed that the fetus had normal chromosomes and did not carry the c.544-2A>G variant. The copy number of chromosomes at different parts of placenta was normal after birth. CONCLUSION For couples affected with monogenic disorders, e.g., osteogenesis imperfecta, direct detection of the mutation site may be used for PGT after identifying the pathogenic variant. After adequate genetic counseling, prenatal diagnosis must be carried out to ensure the result.
Aneuploidy ; China ; Female ; Genetic Testing ; Humans ; Osteogenesis Imperfecta/genetics* ; Pregnancy ; Preimplantation Diagnosis

The ongoing development of high-throughput sequencing technology and continuous decline of sequencing cost have made it possible to carry out large-scale screening for genetic diseases, which are the main component of birth defects. The screening of genetic diseases is expected to significantly reduce the rate of birth defects and the burden of genetic diseases to the affected families and the society. Taking Down syndrome as an example, through the analysis of the cost-benefit ratio of relevant screening programs, this article has summarized the socio-economic indicators to be considered during the design and development of genetic disease screening.
Cost-Benefit Analysis ; Down Syndrome/genetics* ; Genetic Testing ; Humans

OBJECTIVE: To carry out genetic testing for an abortus suspected with Cornelia de Lange syndrome (CdLS). METHODS: History of gestation and the family was taken. Combined with prenatal ultrasonography and the phenotype of the abortus, a diagnosis was made for the proband. Fetal tissue and peripheral blood samples of its parents were collected for the extraction of genomic DNA. Whole exome sequencing was carried out to detect mutations related to the phenotype. Suspected mutations were verified in the parents through Sanger sequencing. RESULTS: Prenatal ultrasound found that the forearms and hands of the fetus were anomalous, in addition with poorly formed vermis cerebellum, slight micrognathia, and increased echo of bilateral renal parenchyma. Examination of the abortus has noted upper limb and facial malformations. Whole exome sequencing revealed that the fetus carried a heterozygous c.2118delG (p.Lys706fs) frameshift mutation of the NIPBL gene. The same mutation was not found in either parent. CONCLUSION The heterozygous c.2118delG (p.Lys706fs) frameshift mutation of the NIPBL gene probably underlies the CdLS in the fetus. Above finding has provided a basis for the genetic counseling for the family.
Cell Cycle Proteins/genetics* ; DNA Mutational Analysis ; De Lange Syndrome/pathology* ; Female ; Fetus ; Humans ; Male ; Mutation ; Phenotype ; Pregnancy ; Whole Exome Sequencing

OBJECTIVE: To analyze the clinical phenotype and genetic characterization of a child with early infantile epileptic encephalopathy. METHODS: The proband was subjected to history taking and was diagnosed based on his clinical manifestation, magnetic resonance imaging (MRI) and whole exome sequencing (WES). Sanger sequencing was carried out to determine the origin of pathogenic variant. RESULTS: The proband unconsciously tilts his head to one side with squint, which revealed an abnormal discharge. MRI indicated suspicious abnormal signal shadow in the left posterior frontal cortex in addition with inflammation signs in the right maxillary sinus and ethmoid sinus. WES revealed that the proband has carried a heterozygous c.5789G>A variant in the CACNAIA gene. The result of Sanger sequencing was in keeping with that of WES. Neither of his parents has carried the same variant. CONCLUSION The heterozygous c.5789G>A variant of the CACNAIA gene probably underlay the early infantile epileptic encephalopathy 42 in the proband, which has a de novo origin.
Calcium Channels/genetics* ; Genetic Testing ; Heterozygote ; Humans ; Infant ; Mutation ; Spasms, Infantile/genetics* ; Whole Exome Sequencing

OBJECTIVE: To apply nanopore third-generation sequencing for the detection of chromosomal aneuploidy samples, and explore its performance and application prospects. METHODS: DNA extracted from two human cell lines with X chromosome monosomy and 22.5 Mb deletion in 7q11.23-q21.3 region was sequenced with a MinION sequencer, and the results were analyzed. RESULTS: Respectively, 555 872 and 2 679 882 reads were obtained from the two samples within 24 hours, with genome coverage being 53.75% and 88.63%. With a sequencing depth of 0.81× and 2.40× , respectively, the abnormal chromosomal regions could be detected by comparative analysis using Minimap2. CONCLUSION With low-depth whole genome sequencing, the use of nanopore third-generation sequencing is expected to complete the detection and analysis of chromosomal aneuploidy samples within 24 hours, but its further application and promotion needs to overcome the cost constraints.
Aneuploidy ; Chromosomes ; High-Throughput Nucleotide Sequencing ; Humans ; Sequence Analysis, DNA ; Technology

Clinical practice of Medical Genetics involves application of various genetic techniques for the diagnosis of genetic disorders and subsequent genetic counseling and treatment. The principles of Medical Ethics must be fully taken into account when applying genetic knowledge for medical practice. Medical Ethics education is therefore essential for the standardized training of resident doctors in medical genetics department. With a basic system of Medical Genetics Physician Training established, our hospital has made a preliminary exploration for the development of Medical Ethics teaching in resident training through various teaching practices including seminar, network teaching, case study, scene teaching and outpatient teaching, with an aim to strengthen Medical Ethnics knowledge, professionalism and communication skills, and implement Medical Ethics principles throughout clinical practice.
Curriculum ; Educational Status ; Ethics, Medical ; Genetics, Medical ; Humans

OBJECTIVE: To diagnose a fetus with Papillorenal syndrome by prenatal ultrasonography and genetic testing, and to correlate its genotype with phenotype. METHODS: Ultrasound finding of the fetus was reviewed. Muscle sample of the abortus was taken, and genetic variant related to the clinical phenotype was screened by whole exome sequencing (WES). Suspected pathogenic variant was verified by Sanger sequencing. RESULTS: Prenatal ultrasound revealed severe dysplasia of the fetal kidneys and oligohydramnios. WES revealed that the fetus has carried a c.736G>T (p.Glu246Ter) nonsense variant of the PAX2 gene, which was unreported previously. The result of Sanger sequencing was consistent with that of WES. Both parents of the fetus were of the wild-type, suggesting a de novo origin of the fetal variant. CONCLUSION The novel heterozygous c.736G>T (p.Glu246Ter) variant of the PAX2 gene probably underlay the Papillorenal syndrome in the fetus. Above finding has provided a basis for genetic counseling and clinical decision-making.

OBJECTIVE: To explore the genetic basis for fetus with short limbs detected by prenatal ultrasonography. METHODS: Results of clinical imaging of the fetus was collected. Amniotic fluid sample was collected through amniocentesis for the extraction of fetal DNA. Whole exome sequencing was carried out to detect variants related to the clinical phenotypes. Candidate variant was verified by Sanger sequencing. RESULTS: Prenatal ultrasound showed that the fetus had short limbs but no other abnormality. Whole exome sequencing has identified that the fetus carried two heterozygous pathogenic variants c.484G>T and c.1436dupA of the SLC26A2 gene, for which its mother and father were heterozygous carriers, respectively. CONCLUSION The fetus was diagnosed with atelosteogenesis type 2 by combined prenatal ultrasonography and whole exome sequencing, which may be attributed to the compound heterozygous variants of the SLC26A2 gene. Above findings provided evidence for the diagnosis of the fetus and genetic counseling.

OBJECTIVE: To report on echocardiographic finding and genetic testing of three fetuses with cardiac rhabdomyoma. METHODS: Clinical data of the three fetuses was collected. High-throughput sequencing was carried out to analyze the whole exomes of the three fetuses. Suspected variants were confirmed by Sanger sequencing. RESULTS: Multiple hyperechoic masses were found in both ventricles of the three fetuses, suggesting the presence of fetal cardiac rhabdomyoma. Genetic testing revealed that fetus 1 carried a heterozygous c.740G>A (p.W247*) variant of the TSC1 gene, fetus 2 carried a previously known heterozygous c.3352C>T (p.Q1118*) variant of the TSC2 gene. Fetus 3 carried a previously known heterozygous c.1579C>T (p.Q527*) variant of the TSC1 gene. None of their parents carried the same variant. Literature review has identified 109 fetuses with relatively complete data. Cardiac rhabdomyomas in ventricles and ventricular septum was reported in 89, and multiple cardiac rhabdomyoma was reported in 79. Out of the 94 cases who underwent genetic testing, 74 have carried variants of the TSC1 or TSC2 genes. CONCLUSION Fetal cardiac rhabdomyoma may present as multiple hyperechoic intraventricular masses. Most of them are associated with other manifestation of tuberous sclerosis. Such cases may warrant prenatal genetic testing.