Application of short tandem repeats (STRs) in the preimplantation genetic diagnosis (PGD) of α-thalassemia.

Objectives: α-thalassemia is an autosomal recessive monogenic blood disorder, affecting up to 5% of the world's population. The occurrence rate of the disease in Vietnam varies up to up to 51.5%, with high rate of mutation carriers, of couples consisting of two carriers at risk of bearing a child with fetal Hb Bart, which can develop into hydrops fetalis syndrome, threatening the well-being of the mother and the child.

A novel variant and clinical diversity in Vietnamese SMARD1 and CMT2S patients.

Background: Pathogenic variants in the gene are associated with two distinct autosomal recessive neuromuscular disorders: spinal muscular atrophy with respiratory distress type 1 (SMARD1; OMIM #604320) and Charcot-Marie-Tooth type 2S (CMT2S; OMIM #616155). SMARD1 is a severe and fatal condition characterized by infantile-onset respiratory distress, diaphragmatic palsy, and distal muscular weakness, while CMT2S follows a milder clinical course, with slowly progressive distal muscle weakness and sensory loss, without manifestations of respiratory disorder.

Methods: Whole-exome sequencing of the gene was performed for eight Vietnamese patients with -related neuromuscular disorders including five patients with SMARD1 and the others with CMT2S.

Mutation spectrum of retinoblastoma patients in Vietnam.

Background: Retinoblastoma (RB), an intraocular malignancy commonly diagnosed in children, is mostly caused by inactivating mutations of both alleles of the RB1 gene. Early genetic screening for RB1 gene mutations would greatly improve treatment outcomes and patient management.

Methods: In this study, both somatic and germline mutations were detected in blood and tumour samples of 42 RB patients using direct sequencing and multiplex ligation-dependent probe amplification.

In silico validation revealed the role of SCN5A mutations and their genotype-phenotype correlations in Brugada syndrome.

Background: Brugada syndrome (BrS) is a rare genetic disease that causes sudden cardiac death (SCD) and arrhythmia. SCN5A pathogenic variants (about 30% of diagnosed patients) are responsible for BrS.

Aims: Lack of knowledge regarding molecular characteristics and the correlation between genotype and phenotype interfere with the risk stratification and finding the optimal treatment in Vietnam.

Targeted next-generation sequencing determined a novel variant that is associated with limb-girdle muscular dystrophy type 2C: A case report.

Limb-girdle muscular dystrophy-type 2C (LGMD2C) is caused by mutations in the gene. Here, we report a case of a 26-year-old male who had inactive walking due to proximal muscle weakness. Targeted next-generation sequencing found a novel variant c.

Feasibility of combining short tandem repeats (STRs) haplotyping with preimplantation genetic diagnosis (PGD) in screening for beta thalassemia.

β-thalassemia is an autosomal recessive disease with the reduction or absence in the production of β-globin chain in the hemoglobin, which is caused by mutations in the Hemoglobin subunit beta (HBB) gene. In Vietnam, the number of β-thalassemia carriers range from 1.5 to 25.

Preimplantation genetic testing (PGT) for hemophilia A: Experience from one center.

Objective: Hemophilia A (HA) is an X-linked recessive bleeding disease caused by a deficiency or dysfunction of blood coagulation factor VIII (FVIII). Available treatment to replenish the missing factor may not reach a good outcome for all patients because of potential complications that include the development of inhibitor antibodies directed against factor VIII. Therefore, the prevention of transmitting pathogenic mutations to the next generation is the best solution for this disease.

Molecular Characterization and Genotype-Phenotype Correlation of G6PD Mutations in Five Ethnicities of Northern Vietnam.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme disorder and is caused by G6PD gene mutations. To date, more than 400 variants in the G6PD gene have been discovered, and about 160 identified variants are associated with a significant decrease in the G6PD enzyme activity. However, the molecular characterization and epidemiological study of G6PD deficiency are still limited in Vietnam.

Prenatal diagnosis of atrioventricular discordance with ventriculoarterial concordance by fetal echocardiography: A case report.

Objective: To report an extremely rare case of atrioventricular discordance and ventriculoarterial concordance associated with a ventricular septal defect which was diagnosed prenatally.

Case Report: By fetal echocardioraphy at 20 weeks' gestation, we diagnosed a rare case of atrioventricular discordance and ventriculoarterial concordance associated with a ventricular septal defect. This is the first case reported from Vietnam prenatally.

Whole exome sequencing analysis in a couple with three children who died prematurely due to carnitine-acylcarnitine translocase deficiency.

Objective: We investigated a strategy of exome sequencing DNA from the unaffected parents and applied a set of filtering criteria to identify genes where both partners are heterozygous for a potentially pathogenic variant.

Case Report: We report a non-consanguineous couple who had three daughters, all spontaneous preterm birth at 36 weeks gestation and died in the first period after birth, suspected inborn errors of metabolism. Two days after birth, the first daughter presented with difficulty breathing, cyanosis and died; the second died at 33 days old; the third daughter was isolated under special care and was taken to the mother's room, developed the same symptoms and died after 5 days.

Microcephaly primary hereditary (MCPH): Report of novel ASPM variants and prenatal diagnosis in a Vietnamese family.

Objective: MCPH (microcephaly primary hereditary) is a group of autosomal recessive developmental disorders with microcephaly present at birth and intellectual disability. Since a second trimester ultrasound is not able to detect subtypes with minimal prenatal presentations, only prenatal diagnosis by genetic testing can confirm these cases and allow for effective genetic counseling, especially a family with a previously affected child.

Case Report: A 37-year-old women was pregnant for the third time and had two prior children with profound microcephaly and mental retardation.

A case of self-improving collodion ichthyosis in Vietnam.

Autosomal recessive congenital ichthyosis is a heterogeneous group of congenital disorders characterized by aberrant skin cornification and diffuse skin scaling. Some patients with this condition are born encased in a collodion membrane which is later shed, revealing the underlying skin disorder. Self-healing collodion baby (SHCB) is a less common phenotype of this disorder, accounting for about 10% of the patients, in which the membrane peels after several weeks, leaving no underlying skin aberration.

Assessment of 6 STR loci for prenatal diagnosis of Duchenne Muscular Dystrophy.

Objective: Duchenne Muscular Dystrophy is an X-linked recessive disorder characterized by progressive muscular degeneration, patients often develop cardiac failure in the later stage and death occurs before 20 years of age. For a disease with poor postnatal prognosis such as Duchenne Muscular Dystrophy (DMD), providing the carrier mother with the option of prenatal diagnosis in a subsequent pregnancy is accepted practice in many places where termination of pregnancy is allowed. Though methods of direct sequencing such as Sanger's sequencing has been widely used, Next-Generation Sequencing is been increasingly replacing most of its application.

Acromesomelic dysplasia Maroteaux-type in patients from Vietnam.

Acromesomelic dysplasias are rare skeletal disorders leading to severe short stature and abnormal skeletal morphology. Acromesomelic dysplasia Maroteaux-type is caused by homozygous or compound heterozygous pathogenic variants in NPR2 that encodes for natriuretic peptide receptor B. Here, we reported the first AMDM case in South East Asia and identified a novel pathogenic variant in NPR2 (c.

Novel variants of CYP21A2 in Vietnamese patients with congenital adrenal hyperplasia.

Background: Congenital adrenal hyperplasia (CAH) (OMIM #201910) is a complex disease most often caused by pathogenic variant of the CYP21A2 gene. We have designed an efficient multistep approach to diagnose and classify CAH cases due to CYP21A2 variant and to study the genotype-phenotype relationship.

Methods: A large cohort of 212 Vietnamese patients from 204 families was recruited.

Mosaicism in carrier of Duchenne muscular dystrophy mutation - Implication for prenatal diagnosis.

Objective: Duchenne muscular dystrophy (DMD) is a severe disorder caused by mutation in the X-linked dystrophin gene, therefor carrier testing is required for all female family members. However, there are cases mutation analysis cannot detect any mutation due to a phenomenon called mosaicism. The case report describes a case of mosaicism in a DMD carrier and discusses the approach in diagnosis and counseling of familial disorder.

Prenatal diagnosis of a case with SEA-HPFH deletion thalassemia with whole HBB gene deletion.

Objective: The thalassemias is a group of hereditary disorders with impaired production of functional hemoglobin. In this report we described a rare case of compound heterozygous mutation of South-East Asia type hereditary persistence of fetal hemoglobin (SEA-HPFH) and β -thalassemia that allowed prenatal diagnosis to be performed in a subsequent pregnancy in the family.

Case Report: The father showed a SEA-HPFH thalassemia trait phenotype, while his genotype revealed that he was heterozygous for the SEA-HPFH deletion; The mother genotype was heterozygote for IVS-II-654 mutation; the second child had co-inherited both parental mutations and was, thus, a compound heterozygote for β-thalassemia (IVS-II-654)/SEA-HPFH deletion.

Genetic analysis of 55 northern Vietnamese patients with Wilson disease: seven novel mutations in ATP7B.

Wilson disease (WD) is an autosomal recessive disorder of copper metabolism. The gene responsible for WD was discovered in 1993 and is located on chromosome 13 at 13q14.3.

Rapid method for targeted prenatal diagnosis of Duchenne muscular dystrophy in Vietnam.

Objective: Since there is no effective curative treatment for Duchenne muscular dystrophy (DMD), prevention mostly depends on genetic counseling and prenatal diagnosis. About two-thirds of the affected patients have large deletions or duplications, which can be detected by multiplex ligation-dependent amplification (MLPA). The remaining cases include small mutations, which cannot be easily identified by routine techniques.

Establishing a national program for fetoscopic guided laser occlusion for twin-to-twin transfusion syndrome in Sweden.

Objective: To describe the establishment of the fetoscopic guided laser occlusion (FLOC) technique for treatment of twin-to-twin transfusion syndrome (TTTS) and the initial results in a Swedish national center.

Design: Retrospective, descriptive study.

Setting: Tertiary level university hospital.