Explore the vast range of titles available.

Purpose To characterize the molecular genetics of autosomal recessive Noonan syndrome. Methods Families underwent phenotyping for features of Noonan syndrome in children and their parents. Two multiplex families underwent linkage analysis. Exome, genome, or multigene panel sequencing was used to identify variants. The molecular consequences of observed splice variants were evaluated by reverse-transcription polymerase chain reaction. Results Twelve families with a total of 23 affected children with features of Noonan syndrome were evaluated. The phenotypic range included mildly affected patients, but it was lethal in some, with cardiac disease and leukemia. All of the parents were unaffected. Linkage analysis using a recessive model supported a candidate region in chromosome 22q11, which includes LZTR1 , previously shown to harbor mutations in patients with Noonan syndrome inherited in a dominant pattern. Sequencing analyses of 21 live-born patients and a stillbirth identified biallelic pathogenic variants in LZTR1 , including putative loss-of-function, missense, and canonical and noncanonical splicing variants in the affected children, with heterozygous, clinically unaffected parents and heterozygous or normal genotypes in unaffected siblings. Conclusion These clinical and genetic data confirm the existence of a form of Noonan syndrome that is inherited in an autosomal recessive pattern and identify biallelic mutations in LZTR1 .

Background/Objectives: Children with congenital adrenal hyperplasia (CAH) face significant risks of impaired growth and metabolic disturbances despite standard glucocorticoid therapy. This cross-sectional study aimed to evaluate growth outcomes, nutritional status, and associated factors among children with CAH treated in a Vietnamese tertiary pediatric center. Methods: We assessed 201 children aged 1.1–16.5 years in a tertiary pediatric center in Vietnam for anthropometric parameters, biochemical markers (calcium, phosphate, 25-hydroxyvitamin D), and clinical features. Growth status was evaluated using WHO standards, and bone age was assessed radiographically. Statistical analyses explored associations between growth outcomes and clinical, biochemical, and treatment-related factors. Results: Stunting was present in 16.4% of children, while 53.3% were overweight or obese. Bone age advancement occurred in 51.7% of cases. Vitamin D insufficiency or deficiency was detected in 85.6% of patients, and hypocalcemia was present in 85.1%. Overweight/obesity, vitamin D deficiency, and bone age advancement were associated with older age, prolonged corticosteroid therapy, higher androgen levels, and clinical features of treatment imbalance (e.g., Cushingoid appearance, hyperpigmentation). Female sex was significantly associated with higher rates of stunting. Conclusions: Growth impairment, nutritional deficiencies, and skeletal maturation disturbances are prevalent among children with CAH in Vietnam. Early identification of risk factors and the implementation of tailored management strategies that address both endocrine and nutritional health are crucial for optimizing long-term outcomes.

Beta-ketothiolase (T2) deficiency is an inherited disease of isoleucine and ketone body metabolism caused by mutations in the ACAT1 gene. Between 2005 and 2016, a total of 41 patients with T2 deficiency were identified at a medical center in northern Vietnam, with an estimated incidence of one in 190,000 newborns. Most patients manifested ketoacidotic episodes of varying severity between 6 and 18 months of age. Remarkably, 28% of patients showed high blood glucose levels (up to 23.3 mmol/L). Ketoacidotic episodes recurred in 43% of patients. The age of onset, frequency of episodes, and identified genotype did not affect patient outcomes that were generally favorable, with the exception of seven cases (five died and two had neurological sequelae). Custom-tailored acute and follow-up management was critical for a positive clinical outcome. Two null mutations, c.622C>T (p.Arg208*) and c.1006-1G>C (p.Val336fs), accounted for 66% and 19% of all identified ACAT1 mutant alleles, respectively. Most patients showed characteristic biochemical abnormalities. A newborn screening program could be expected to have a high yield in Vietnam. Investigation findings of haplotypes linked to the most common ACAT1 mutation (c.622C>T) are consistent with an ancient common founder of mutation-bearing chromosomes belonging to the Kinh ethnic population. The direct management and long-term follow-up of a large number of T2-deficient patients enabled us to study the natural history of this rare disease.

Cornelia de Lange Syndrome (CdLS) is a rare congenital genetic disease causing abnormal unique facial phenotypes, several defects in organs and body parts, and mental disorder or intellectual disorder traits. Main causes of CdLS have been reported as variants in cohesin complex genes, in which mutations in the NIPBL gene have been estimated to account for up to 80%. Our study included three Vietnamese patients with typical CdLS phenotypes. Whole exome sequencing revealed two known heterozygous mutations c.6697G>A (p.Val2233Met) and c.2602C>T (p.Arg868X), and a novel heterozygous mutation c.4504delG (p.Val1502fsX87) in the NIPBL gene of the three patients. In silico analyses of the identified mutations predicted possible damaging and truncating effects on the NIPBL protein. Inherited analyses in the patients’ families showed that all of the mutations are de novo. Our results lead a definitive diagnosis of patients with CdLS and expand the spectrum of mutations in the NIPBL gene. These findings also confirm whole exome sequencing is an efficient tool for genetic screening of CdLS.

Mucopolysaccharidoses (MPS) and mucolipidosis (ML II/III) are a group of lysosomal storage disorders (LSDs) that occur due to a dysfunction of the lysosomal hydrolases responsible for the catabolism of glycosaminoglycans (GAGs). However, ML is caused by a deficiency of the enzyme uridine-diphosphate N-acetylglucosamine:lysosomal-enzyme-N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase, EC2.7.8.17), which tags lysosomal enzymes with a mannose 6-phosphate (M6P) marker for transport to the lysosome. A timely diagnosis of MPS and ML can lead to appropriate therapeutic options for patients. To improve the accuracy of diagnosis for MPS and ML in a high-risk population, we propose a combination method based on known biomarkers, enzyme activities, and specific GAGs. We measured five lysosomal enzymes (α-L-iduronidase (MPS I), iduronate-2-sulfatase (MPS II), α-N-acetylglucosaminidase (MPS IIIB), N-acetylglucosamine-6-sulfatase (MPS IVA), and N-acetylglucosamine-4-sulfatase (MPS VI)) and five GAGs (two kinds of heparan sulfate (HS), dermatan sulfate (DS), and two kinds of keratan sulfate (KS)) in dried blood samples (DBS) to diagnose suspected MPS patients by five-plex enzyme and simultaneous five GAGs assays. We used liquid chromatography-tandem mass spectrometry (LC-MS/MS) for both assays. These combined assays were tested for 43 patients with suspected MPS and 103 normal control subjects. We diagnosed two MPS I, thirteen MPS II, one MPS IIIB, three MPS IVA, two MPS VI, and six ML patients with this combined method, where enzymes, GAGs, and clinical manifestations were compatible. The remaining 16 patients were not diagnosed with MPS or ML. The five-plex enzyme assay successfully identified MPS patients from controls. Patients with MPS I, MPS II, and MPS IIIB had significantly elevated HS and DS levels in DBS. Compared to age-matched controls, patients with ML and MPS had significantly elevated mono-sulfated KS and di-sulfated KS levels. The results indicated that the combination method could distinguish these affected patients with MPS or ML from healthy controls. Overall, this study has shown that this combined method is effective and can be implemented in larger populations, including newborn screening.

BackgroundGenomic imprinting results from the resistance of germline epigenetic marks to reprogramming in the early embryo for a small number of mammalian genes. Genetic, epigenetic or environmental insults that prevent imprints from evading reprogramming may result in imprinting disorders, which impact growth, development, behaviour and metabolism. We aimed to identify genetic defects causing imprinting disorders by whole-exome sequencing in families with one or more members affected by multilocus imprinting disturbance.MethodsWhole-exome sequencing was performed in 38 pedigrees where probands had multilocus imprinting disturbance, in five of whom maternal variants in NLRP5 have previously been found.ResultsWe now report 15 further pedigrees in which offspring had disturbance of imprinting, while their mothers had rare, predicted-deleterious variants in maternal effect genes, including NLRP2, NLRP7 and PADI6. As well as clinical features of well-recognised imprinting disorders, some offspring had additional features including developmental delay, behavioural problems and discordant monozygotic twinning, while some mothers had reproductive problems including pregnancy loss.ConclusionThe identification of 20 putative maternal effect variants in 38 families affected by multilocus imprinting disorders adds to the evidence that maternal genetic factors affect oocyte fitness and thus offspring development. Testing for maternal-effect genetic variants should be considered in families affected by atypical imprinting disorders.

Hypopituitarism is a condition characterized by the deficiency of several hormones produced by the pituitary gland. Genetic factors play an important role. Variants in the POU1F1 gene are associated with combined pituitary hormone deficiency 1 (CPHD1), which manifests as deficiencies in growth hormone (GH), thyroid-stimulating hormone (TSH), and prolactin (PRL). This study aimed to analyze the phenotype, genotype, treatment, and outcomes of Vietnamese patients with deficiency. Six patients from five unrelated families, initially diagnosed with hypopituitarism, were enrolled in this study. Data on physical characteristics, biochemical tests, treatment, outcomes, and follow-up were collected. Exome sequencing and Sanger sequencing were conducted to identify disease-causing variants in five probands and their families. All six patients exhibited anterior pituitary hypoplasia on brain magnetic resonance imaging and presented with TSH, GH, and PRL deficiencies. Exome sequencing identified three variants in the POU1F1 gene: c.428G>A p.(Arg143Gln), c.557T>G p.(Leu186Arg), and c.811C>T p.(Arg271Trp). The c.811C>T p.(Arg271Trp) variant was found in three patients, while c.557T>G p.(Leu186Arg) is a novel variant. Based on the ACMG classification, these variants were categorized as likely pathogenic or pathogenic variants. All patients were definitively diagnosed with CPHD1 caused by POU1F1 variants. All patients received levothyroxine and recombinant human growth hormone (rhGH) replacement therapy, leading to considerable growth. During the first year of treatment, all patients showed excellent growth response, with height increases ranging from 11 to 24 cm. After three years of treatment, two patients achieved normal height. One of the six patients developed scoliosis during treatment, which resolved after a one-year pause in rhGH therapy. Upon resuming treatment, no recurrence of scoliosis was observed. Our findings reveal the importance of early hormone testing and genetic analysis in improving the care and outcomes for patients with combined pituitary hormone deficiency.

Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase deficiency (HMGCS2D) is a rare metabolic disorder that impairs the body’s ability to produce ketone bodies and regulate energy metabolism. Diagnosing HMGCS2D is challenging because patients typically remain asymptomatic unless they experience fasting or illness. Due to the absence of reliable biochemical markers, genetic testing has become the definitive method for diagnosing HMGCS2D. This study included 19 patients from 14 unrelated families diagnosed with HMGCS2D in our department between October 2018 and October 2024. The clinical presentations, biochemical findings, molecular characteristics, and management strategies were systematically summarized and analyzed. Of the 19 cases studied, 16 were symptomatic, and 3 were asymptomatic. The onset of the first acute episode occurred between 10 days and 28 months of age. Triggers for the initial crisis in the symptomatic cases included poor feeding (93.8%), vomiting (56.3%), diarrhea (25.0%), and fever (18.8%). Clinical manifestations during the first episode were lethargy/coma (81.3%), rapid breathing (68.8%), hepatomegaly (56.3%), shock (37.5%), and seizures (18.8%). The biochemical abnormalities observed included elevated plasma transaminases (100%), metabolic acidosis (75%), hypoglycemia (56.3%), and elevated plasma ammonia levels (31.3%). Additionally, low free carnitine levels were found in seven cases, elevated C2 levels were found in one case, dicarboxylic aciduria was found in two cases, and ketonuria was found in two cases. Abnormal brain MRI findings were detected in three patients. Genetic analysis revealed seven HMGCS2 gene variants across the 19 cases. Notably, a novel variant, c.407A>T (p.D136V), was identified and has not been reported in any existing databases. Two common variants, c.559+1G>A and c.1090T>A (p.F364I), were present in 11 out of 19 cases (57.9%) and 10 out of 19 cases (55.5%), respectively. The implementation of a high glucose infusion and proactive management strategies—such as preventing prolonged fasting and providing enteral carbohydrate/glucose infusion during illness—effectively reduced the rate of acute relapses following accurate diagnosis. Currently, all 19 patients are alive, with ages ranging from 5 months to 14 years, and exhibit normal physical development. To the best of our knowledge, this study represents the first reported cases of HMGCS2D in Vietnamese patients. Our findings contribute to a broader understanding of the clinical phenotype and expand the known spectrum of HMGCS2 gene variants, enhancing current knowledge of this rare metabolic disorder.

The pancreatic ATP-sensitive K+ (K-ATP) channel is a key regulator of insulin secretion. Gain-of-function mutations in the genes encoding the Kir6.2 (KCNJ11) and SUR1 (ABCC8) subunits of the channel cause neonatal diabetes, whilst loss-of-function mutations in these genes result in congenital hyperinsulinism. We report two patients with neonatal diabetes in whom we unexpectedly identified recessively inherited loss-of-function mutations. The aim of this study was to investigate how a homozygous nonsense mutation in ABCC8 could result in neonatal diabetes. The ABCC8 p.Glu747* was identified in two unrelated Vietnamese patients. This mutation is located within the in-frame exon 17 and RNA studies confirmed (a) the absence of full length SUR1 mRNA and (b) the presence of the alternatively spliced transcript lacking exon 17. Successful transfer of both patients to sulphonylurea treatment suggests that the altered transcript expression enhances the sensitivity of the K-ATP channel to Mg-ADP/ATP. This is the first report of an ABCC8 nonsense mutation causing a gain-of-channel function and these findings extend the spectrum of K-ATP channel mutations observed in patients with neonatal diabetes.

Background and Objectives: Hyperornithinemia–hyperammonemia–homocitrullinuria syndrome (HHH; OMIM 238970) is one of the rare urea cycle disorders. Ornithine carrier 1 deficiency causes HHH syndrome, characterized by failure of mitochondrial ornithine uptake, hyperammonemia, and accumulation of ornithine and lysine in the cytoplasm. The initial presentation and time of diagnosis in HHH highly varies. Genetic analysis is critical for diagnosis. Materials and Methods: This study encompassed retrospective and prospective analyses of four unrelated Vietnamese children diagnosed with HHH syndrome. Results: The age of diagnosis ranged from 10 days to 46 months. All four cases demonstrated hyperornithinemia and prolonged prothrombin time. Three out of four cases presented with hyperammonemia, elevated transaminases, and uraciluria. No homocitrulline was detected in the urine. Only one case depicted oroticaciduria. Genetic analyses revealed three pathogenic variants in the SLC25A15 gene, with the c.535C>T (p.Arg179*) variant common in Vietnamese patients. The c.562_564del (p.Phe188del) and c.408del (p.Met137Cysfs*10) variants were detected in one case. The latter variant has yet to be reported in the literature on HHH patients. After intervention with a protein-restricted diet, ammonia-reducing therapy, and L-carnitine supplementation, hyperammonemia was not observed, and liver enzyme levels returned to normal. Conclusions: Our results highlighted the clinical and biochemical heterogeneity of HHH syndrome and posed that HHH syndrome should be considered when individuals have hyperammonemia, elevated transaminase, and decreased prothrombin time.