Shift from a Zero-COVID strategy to a New-normal strategy for controlling SARS-COV-2 infections in Vietnam.

The aim of this study is to analyse the changing patterns in the transmission of COVID-19 in relation to changes in Vietnamese governmental policies, based on epidemiological data and policy actions in a large Vietnamese province, Bac Ninh, in 2021. Data on confirmed cases from January to December 2021 were collected, together with policy documents. There were three distinct periods of the COVID-19 pandemic in Bac Ninh province during 2021. During the first period, referred to as the 'Zero-COVID' period (01/04-07/04/2021), there was a low population vaccination rate, with less than 25% of the population receiving its first vaccine dose. Measures implemented during this period focused on domestic movement restrictions, mask mandates, and screening efforts to control the spread of the virus. The subsequent period, referred to as the 'Transition' period (07/05-10/22/2021), witnessed a significant increase in population vaccination coverage, with 80% of the population receiving their first vaccine dose. During this period, several days passed without any reported COVID-19 cases in the community. The local government implemented measures to manage domestic actions and reduce the time spent in quarantine, and encouraged home quarantining for the close contacts of cases with COVID-19. Finally, the 'New-normal' stage (10/23-12/31/2021), during which the population vaccination coverage with a second vaccine dose increased to 70%, and most of the mandates for the prevention and control of COVID-19 were reduced. In conclusion, this study highlights the importance of governmental policies in managing and controlling the transmission of COVID-19 and provides insights for developing realistic and context-specific strategies in similar settings.

A Novel Nonsense Mutation c.374C>G in CYP21A2 Gene of a Vietnamese Patient with Congenital Adrenal Hyperplasia.

Inactivating mutations of the CYP21A2 gene, encoding for steroid synthesis, have been reported in patients with congenital adrenal hyperplasia (CAH). We report a case of an infant who were diagnosed with CAH and presented with the severe phenotype of CAH with symptoms such as increased testicular volume, elevated of 17-hydroxyprogesteron, testosterone and progesterone. In this study, we established an assay for the detection of unusual genetic in the CYP21A2 gene in the proband and his family. A novel nonsense mutation c.374C > G which caused a substitutions of Serine for a stop codon at codon 125 (p.S125*) within exon 3 was found in the proband. Parental genotype studies confirmed carrier state in the father, but the mother showed a wild allele by PCR and sequencing. This inspired us to find deletions using multiplex ligation-dependent probe amplification (MLPA) technique. The probands were found to have a large deletion in exons 1 and 3, while the mother only had deletion in exon 1. Therefore, mutation c.374C > G (p.S125*) in the proband is considered as a heterozygous deletion. This mutation caused a truncated protein which lead to the salt wasting CAH phenotype of the proband. This novel nonsense mutation expands the CYP21A2 mutation spectrum in CAH disorder. This case also highlights the need of caution when interpreting results of molecular genetic testing during genetic counseling.

Variation of Mitochondrial DNA HV1 AND HV2 of the Vietnamese Population.

BACKGROUND: The sequence polymorphism of mitochondrial DNA (mtDNA) hypervariable segment 1 (HV1) and hypervariable segment 2 (HV2) is studied and applied to genetic diversity and human evolution assessment, forensic genetics, consanguinity determination, and mitochondrial disease diagnosis. METHODS: The study identified the variations of HV1 and HV2 of 517 unrelated Vietnamese individuals in Kinh, Muong, Cham, and Khmer ethnic. We performed sequencing of two hypervariable segments of mitochondrial DNA: HV1 and HV2. RESULTS: Fifty haplogroups were identified in which F1a haplogroup frequency was highest at 15.7%, followed by B5a (10.8%), M (8.9%), and M7b1 (7.7%). The most frequently encountered SNPs in this study were A263G (100%), A73G (99.6%), 315insC (96%), 309insC (56%), C16223T (41%), and T16189C (39%). The genetic diversity was calculated at 99.83%, and the probability of random match of two individuals sharing the same mtDNA haplotype was 0.37%. CONCLUSION: We have assessed the genetic polymorphism of mtDNA HV1 and HV2 of 517 Kinh, Muong, Cham, and Khmer ethnic samples. The result will help in better understanding of Vietnamese's mitochondrial genome diversity and aid in population as well as forensic science.

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. Here, we report and discuss the diagnosis and management of an infant with SHCB in Vietnam due to compound heterozygous pathogenic mutations in TGM1.

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. 152T>C, p. (Leu51Pro)). Further analyses reveal the parents and two other family members were heterozygous for the variant. The clinical report highlights the importance of molecular genetic testing in diagnosing rare hereditable disease affecting skeletal abnormalities.

Cryptic splice activation but not exon skipping is observed in minigene assays of dystrophin c.9361+1G>A mutation identified by NGS.

Next-generation sequencing (NGS) discloses nucleotide changes in the genome. Mutations at splicing regulatory elements are expected to cause splicing errors, such as exon skipping, cryptic splice site activation, partial exon loss or intron retention. In dystrophinopathy patients, prediction of splicing outcomes is essential to determine the phenotype: either severe Duchenne or mild Becker muscular dystrophy, based on the reading frame rule. In a Vietnamese patient, NGS identified a c.9361+1G>A mutation in the dystrophin gene and an additional DNA variation of A>G at +117 bases in intron 64. To ascertain the consequences of these DNA changes on dystrophin splicing, minigene constructs were prepared inserting dystrophin exon 64 plus various lengths of intron 64. Exon 64 skipping was observed in the minigene construct with 160 nucleotide (nt) of intron 64 sequence with both c.9361+1A and +117G. In contrast, minigene constructs with larger flanking intronic domains resulted in cryptic splice site activation rather than exon skipping. Meanwhile, the cryptic splice site activation was induced even in +117G when intron 64 was elongated to 272 nt and longer. It was expected that cryptic splice site activation is an in vivo splicing outcome.

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) under flooded and unflooded conditions in Hanoi, Vietnam.

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) in Hanoi, Vietnam have been investigated using a low background gamma spectrometer with an HPGe detector (Model-GC5019). Twenty pairs of soil and water spinach samples in two environmental conditions, i.e., flooded and unflooded, were collected for measuring the activity concentrations and determining the soil-to-plant transfer factors (TFs) of natural radionuclides. For water spinach, stems and leaves were collected as the main parts for human consumption and livestock food. The TF of 40K is within the range of 0.32-2.49, which is greater than that of 228Ra (0.01-0.17) and 226Ra (0.01-0.13). The geometric means (geometric standard deviations) of the TFs are 1.17(1.89), 0.05(2.41) and 0.04(1.88) for flooded sites, and 0.89(1.73), 0.03(2.12) and 0.03(1.82) for unflooded sites, respectively. Comparing between the flooded and unflooded sites, the TFs are all greater at the flooded sites.

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. Our study aims to facilitate birth of healthy/asymptomatic children of α-thalassemia carrier couples who received reproductive service at our centre during the period of 2019-2022. MATERIALS AND METHODS: 89 couples at risks of having α-thalassemia offsprings requested IVF procedures and PGD at Post Hospital during 2019-2022 were recruited for investigation. Couple and additional family members' peripheral blood samples of couples and additional family members were subjected to haemoglobin electrophoresis, DNA extraction for α-thalassemia gene mutation detection and STRs linkage analysis. Data were observed and analysed on GeneMarker software. RESULTS: 91 cycles of PGD for α-thalassemia were carried out for 89 couples. α-thalassemia large deletion (--SEA/αα) was the most common mutation identified in 88 couples, in which 4 cases also carried ß-thalassemia point mutations. Combining results of PGS and PGD, 278/424 amplified embryos were transferable (HBA-mutation free or carriers of single heterozygous HBA mutation, without chromosomal abnormality). 64/89 couples have been transferred with the embryos (prioritizing mutation free ones over carriers), resulting in the birth of 36 α-thalassemia disease-free children, 17 ongoing pregnancies, and 11 with miscarriages. CONCLUSION: Successful application of microsatellite-based method in PGD facilitated the birth of 36 healthy children and 17 ongoing pregnancies for 53/64 couples with embryo-transferred. All resulted clinical births displayed confirmation results in line with the PGD results, thus demonstrating the feasibility and credibility of the use of STR markers in PGD.

A novel IGHMBP2 variant and clinical diversity in Vietnamese SMARD1 and CMT2S patients.

Background: Pathogenic variants in the IGHMBP2 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 IGHMBP2 gene was performed for eight Vietnamese patients with IGHMBP2-related neuromuscular disorders including five patients with SMARD1 and the others with CMT2S. Results: We identified one novel IGHMBP2 variant c.1574T > C (p.Leu525Pro) in a SMARD1 patient. Besides that, two patients shared the same pathogenic variants (c.1235 + 3A > G/c.1334A > C) but presented completely different clinical courses: one with SMARD1 who deceased at 8 months of age, the other with CMT2S was alive at 3 years old without any respiratory distress. Conclusion: This study is the first to report IGHMBP-2-related neuromuscular disorders in Vietnam. A novel IGHMBP2 variant c.1574T > C (p.Leu525Pro) expressing SMARD1 phenotype was detected. The presence of three patients with the same genotype but distinct clinical outcomes suggested the interaction of variants and other factors including relating modified genes in the mechanism of various phenotypes.

Exon deletion patterns of the dystrophin gene in 82 Vietnamese Duchenne/Becker muscular dystrophy patients.

Duchenne and Becker muscular dystrophies (DMD/BMD) are the most common inherited muscle diseases caused by mutations in the dystrophin gene. The reading frame rule explains the genotype-phenotype relationship in DMD/BMD. In Vietnam, extensive mutation analysis has never been conducted in DMD/BMD. Here, 152 Vietnamese muscular dystrophy patients were examined for dystrophin exon deletion by amplifying 19 deletion-prone exons and deletion ends were confirmed by dystrophin cDNA analysis if necessary. The result was that 82 (54%) patients were found to have exon deletions, thus confirming exact deletion ends. A further result was that 37 patterns of deletion were classified. Deletions of exons 45-50 and 49-52 were the most common patterns identified, numbering six cases each (7.3%). The reading frame rule explained the genotype-phenotype relationship, but not five (6.1%) DMD cases. Each of five patients had deletions of exons 11-27 in common. The applicability of the therapy producing semifunctional in frame mRNA in DMD by inducing skipping of a single exon was examined. Induction of exon 51 skipping was ranked at top priority, since 16 (27%) patients were predicted to have semifunctional mRNA skipping. Exons 45 and 53 were the next ranked, with 12 (20%) and 11 (18%) patients, respectively. The largest deletion database of the dystrophin gene, established in Vietnamese DMD/BMD patients, disclosed a strong indication for exon-skipping therapy.

Case Report: Novel rare mutation c.6353C > G in the ABCA12 gene causing harlequin ichthyosis identified by whole exome sequencing.

Background: Harlequin ichthyosis (HI) is a severe rare genetic disease that mainly affects the skin. Neonates with this disease are born with thick skin and large diamond-shaped plates covering most of their bodies. Affected neonates lose the ability to control dehydration and regulate temperature and are more susceptible to infections. They also face respiratory failure and feeding problems. These clinical symptoms are factors associated with high mortality rates of neonates with HI. Until now, there are still no effective treatments for HI patients and most patients die in the newborn period. Mutation in the ABCA12 gene, which encodes an adenosine triphosphate-binding cassette (ABC) transporter, has been demonstrated as the major cause of HI. Case presentation: In this study, we report the case who is one infant that was born prematurely at 32 gestational weeks with the whole body covered with thick plate-like scales of skin. The infant was severely infected with mild edema, multiple cracked skins full of the body, yellow discharge, and necrosis of fingers and toes. The infant was suspected to be affected by HI. Whole exome sequencing (WES) was performed as a tool for detecting the novel mutation in one prematurely born Vietnam infant with HI phenotype. And after that, the mutation was confirmed by the Sanger sequencing method in the patient and the members of his family. In this case, one novel mutation c.6353C > G (p.S2118X, Hom) in the ABCA12 gene, was detected in the patient. The mutation has not been reported in any HI patients previously. This mutation was also found in a heterozygous state in the members of the patient's family, including his parents, an older brother, and an older sister who are no symptoms. Conclusions: In this study, we identified a novel mutation in a Vietnamese patient with HI by whole exome sequencing. The results for the patient and the members of his family will be helpful in understanding the etiology of the disease, diagnosing carriers, assisting in genetic counseling, and emphasizing the need for DNA-based prenatal screening for families with a history of the disease.

Novel mutations in the SGCA gene in unrelated Vietnamese patients with limb-girdle muscular dystrophies disease.

Background: Limb-girdle muscular dystrophy (LGMD) is a group of inherited neuromuscular disorders characterized by atrophy and weakness in the shoulders and hips. Over 30 subtypes have been described in five dominant (LGMD type 1 or LGMDD) and 27 recessive (LGMD type 2 or LGMDR). Each subtype involves a mutation in a single gene and has high heterogeneity in age of onset, expression, progression, and prognosis. In addition, the lack of understanding of the disease and the vague, nonspecific symptoms of LGMD subtypes make diagnosis difficult. Even as next-generation sequencing (NGS) genetic testing has become commonplace, some patients remain undiagnosed for many years. Methods: To identify LGMD-associated mutations, Targeted sequencing was performed in the patients and Sanger sequencing was performed in patients and family members. The in silico analysis tools such as Fathmm, M-CAP, Mutation Taster, PolyPhen 2, PROVEAN, REVEL, SIFT, MaxEntScan, Spliceailookup, Human Splicing Finder, NetGene2, and Fruitfly were used to predict the influence of the novel mutations. The pathogenicity of the mutation was interpreted according to the ACMG guidelines. Results: In this study, six patients from four different Vietnamese families were collected for genetic analysis at The Center for Gene and Protein Research and The Department of Molecular Pathology Faculty of Medical Technology, Hanoi Medical University, Hanoi, Vietnam. Based on clinical symptoms and serum creatine kinase (CK) levels, the patients were diagnosed with limb-girdle muscular dystrophies. Five mutations, including four (c.229C>T, p.Arg77Cys; exon one to three deletion; c.983 + 5G>C; and c.257_258insTGGCT, p.Phe88Leufs*125) in the SGCA gene and one (c.946-4_946-1delACAG) in the CAPN3 gene, were detected in six LGMD patients from four unrelated Vietnamese families. Two homozygous mutations (c.983 + 5G>C and c.257_258insTGGCT) in the SGCA gene were novel. These mutations were identified as the cause of the disease in the patients. Conclusion: Our results contribute to the general understanding of the etiology of the disease and provide the basis for definitive diagnosis and support genetic counseling and prenatal screening.

The first Vietnamese patient who presented late onset of pantothenate kinase-associated neurodegeneration diagnosed by whole exome sequencing: A case report.

RATIONALE: Pantothenate kinase-associated neurodegeneration (PKAN), also called Hallervorden-Spatz syndrome, is a rare autosomal recessive disease associated with brain iron accumulation and characterized by progressive dystonia, dementia, and dysarthria symptoms. PKAN, caused by a defective pantothenate kinase 2 (PANK2) gene, is the most common neurodegeneration with a brain iron accumulation (NBIA) group. The "eye of the tiger" sign in the magnetic resonance imaging demonstrated a bilateral hyperintense signal in the basal ganglia region on T2-weighted images, which is a characteristic feature of the diagnosis. PKAN is classified into 2 main types. The early-onset type (classic type) with rapid progression is characterized by symptoms of gait impairment and dystonia leading to loss of ambulation in early childhood. In the later-onset type (atypical type), slow progression usually takes place in the second decade of life with symptoms of neurodegeneration, dystonia, dysarthria, rigidity, choreoathetosis, and motor impairment. Until now, PKAN patients have only been reported in a few countries in Asia such as China, Korea, India, Iran, Taiwan, and Thailand. PATIENT CONCERNS: Here we report the first case of PKAN in Vietnam. The patient had a late onset but the disease progresses rapidly with symptoms of dyskinesia, dysphagia, and difficulty speaking. DIAGNOSES: Pantothenate kinase-associated neurodegeneration. INTERVENTIONS: Whole exome sequencing was performed to identify heterozygous mutations in the PANK2 gene (NM_153638.4) (c.856C>T, p.Arg286Cys and c.1351C>T, p.Arg451Ter) that has been confirmed as the cause of the disease. OUTCOMES: In this study, the first Vietnamese patient with late-onset PKAN was diagnosed by the whole exome sequencing method. LESSONS: The patient's case marks an important milestone for the first case in Vietnam. The results of the study will provide a scientific basis for clinicians in the diagnosis and genetic counseling of patients.

Targeted next-generation sequencing determined a novel SGCG 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 SGCG 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.412C > T (Q138*) in the SGCG gene.

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. Therefore, we identified SCN5A variants and evaluated the genotype-phenotype correlation of BrS on 117 Vietnamese probands. MATERIALS AND METHODS: The clinical characteristics and blood samples of BrS patients were collected. To determine SCN5A variants, Sanger sequencing was conducted, and subsequently, these variants were analyzed by bioinformatic tools. RESULTS: In this cohort, the overall rate of detected variants in SCN5A was 25.6%, which could include both pathogenic and benign variants. In genetic testing, 21 SCN5A variants were identified, including eight novels and 15 published variants. Multiple bioinformatic tools were used to predict variant effect with c.551A>G, c.1890+14G>A, c.3338C>T, c.3578G>A, and c.5484C>T as benign, while other variants were predicted as disease-causing. The family history of SCD (risk ratio [RR] = 4.324, 95% CI: 2.290-8.269, p < 0.001), syncope (RR = 3.147, 95% CI: 1.668-5.982, p = 0.0004), and ventricular tachycardia/ventricular fibrillation (RR = 3.406, 95% CI: 1.722-5.400, p = 0.0035) presented a significantly higher risk in the SCN5A (+) group, consisting of individuals carrying any variant in the SCN5A gene, compared to SCN5A (-) individuals. CONCLUSION: The results contribute to clarifying the impact of SCN5A variants on these phenotypes. Further follow-up studies need to be carried out to understand the functional effects of these SCN5A variants on the severity of BrS.

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. RESULTS: In total, 34 different mutations were found in 36 patients, including 1 SNP, 4 large deletions, 5 splicing sites, 1 missense, 7 frameshifts and 17 nonsense mutations. There were five novel mutations and one unreported which have not been found in large databases such as Leiden Open Variation Database (LOVD) and ClinVar. CONCLUSION: A higher rate of RB patients carrying heterozygous germline mutation and highly prevalent with pathogenic truncated mutation, hence, early detection of RB is essential for vision salvation and genetic counselling.

Merosin-deficient congenital muscular dystrophy type 1a: detection of LAMA2 variants in Vietnamese patients.

Background: Merosin-deficient congenital muscular dystrophy type 1A (MDC1A), also known as laminin-α2 chain-deficient congenital muscular dystrophy (LAMA2-MD), is an autosomal recessive disease caused by biallelic variants in the LAMA2 gene. In MDC1A, laminin- α2 chain expression is absent or significantly reduced, leading to some early-onset clinical symptoms including severe hypotonia, muscle weakness, skeletal deformity, non-ambulation, and respiratory insufficiency. Methods: Six patients from five unrelated Vietnamese families presenting with congenital muscular dystrophy were investigated. Targeted sequencing was performed in the five probands. Sanger sequencing was carried out in their families. Multiplex ligation-dependent probe amplification was performed in one family to examine an exon deletion. Results: Seven variants of the LAMA2 (NM_000426) gene were identified and classified as pathogenic/likely pathogenic variants using American College of Medical Genetics and Genomics criteria. Two of these variants were not reported in the literature, including c.7156-5_7157delinsT and c.8974_8975insTGAT. Sanger sequencing indicated their parents as carriers. The mothers of family 4 and family 5 were pregnant and a prenatal testing was performed. The results showed that the fetus of the family 4 only carries c.4717 + 5G>A in the heterozygous form, while the fetus of the family 5 carries compound heterozygous variants, including a deletion of exon 3 and c.4644C>A. Conclusion: Our findings not only identified the underlying genetic etiology for the patients, but also provided genetic counseling for the parents whenever they have an offspring.

BRCA1/2 Mutations in Vietnamese Patients with Hereditary Breast and Ovarian Cancer Syndrome.

(1) Background: Individuals with BRCA1/2 gene mutations are at increased risk of breast and ovarian cancer. The prevalence of BRCA1/2 mutations varies by race and ethnicity, and the prevalence and the risks associated with most BRCA1/2 mutations has not been unknown in the Vietnamese population. We herein screen the entire BRCA1 and BRCA2 genes for breast and ovarian cancer patients with a family history of breast cancer and ovarian cancer, thereby, suggesting a risk score associated with carrier status and history for aiding personalized treatment; (2) Methods: Between December 2017 and December 2019, Vietnamese patients who had a pathological diagnosis of breast and epithelial ovarian cancer were followed up, prospectively, after treatment from two large institutions in Vietnam. Blood samples from 33 Vietnamese patients with hereditary breast and ovarian cancers (HBOC) syndrome were collected and analyzed using Next Generation Sequencing; (3) Results: Eleven types of mutations in both BRCA1 (in nine patients) and BRCA2 (in three patients) were detected, two of which (BRCA1:p.Tyr1666Ter and BRCA2:p.Ser1341Ter) have not been previously documented in the literature. Seven out of 19 patient's relatives had BRCA1/2 gene mutations. All selected patients were counselled about the likelihood of cancer rising and prophylactic screening and procedures. The study established a risk score associated with the cohorts based on carrier status and family history; (4) Conclusions: Our findings suggested the implications for the planning of a screening programme for BRCA1 and BRCA2 genes testing in breast and ovarian cancer patients and genetic screening in their relatives. BRCA1/2 mutation carriers without cancer should have early and regular cancer screening, and prophylactic measures. This study could be beneficial for a diverse group in a large population-specific cohort, related to HBOC Syndrome.

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. Dried blood spot testing screen of 55 congenital metabolic disorders was negative. CONCLUSION: Heterogenous variant in SLC25A20 gene was found in both parents, contributing to the delineations of the neonatal phenotypes related to SLC25A20 mutation in CACTD.