A novel AP1S2 variant causing leaky splicing in X-linked intellectual disability: Further delineation and intrafamilial variability

Pettigrew syndrome (PGS), an X-linked intellectual disability (XLID), is caused by mutations in the AP1S2 gene. Herein, we described a Thai family with six patients who had severe-to-profound intellectual impairment, limited verbal communication, and varying degrees of limb spasticity. One patient had a unilateral cataract. We demonstrated facial evolution over time, namely coarse facies, long faces, and thick lip vermilions. We identified a novel AP1S2 variant, c.1-2A>G. The mRNA analysis revealed that the variant resulted in splicing defects with leaky splicing, yielding two distinct aberrant transcripts, one of which likely resulting in the mutant protein lacking the first 44 amino acids whereas the other possibly leading to no production of the protein. By performing a literature review, we found 51 patients and 11 AP1S2 pathogenic alleles described and that all the variants were loss-of-function alleles. The severity of ID in Pettigrew syndrome is mostly severe-to-profound (54.8%), followed by moderate (26.2%) and mild. Progressive spasticity was noted in multiple patients. In summary, leaky splicing found in the present family was likely related to the intrafamilial clinical variability. Our data also support the previous notion of variable expression and neuroprogressive nature of the disorder.

An increase in ER stress and unfolded protein response in iPSCs-derived neuronal cells from neuronopathic Gaucher disease patients

Gaucher disease (GD) is a lysosomal storage disorder caused by a mutation in the GBA1 gene, responsible for encoding the enzyme Glucocerebrosidase (GCase). Although neuronal death and neuroinflammation have been observed in the brains of individuals with neuronopathic Gaucher disease (nGD), the exact mechanism underlying neurodegeneration in nGD remains unclear. In this study, we used two induced pluripotent stem cells (iPSCs)-derived neuronal cell lines acquired from two type-3 GD patients (GD3-1 and GD3-2) to investigate the mechanisms underlying nGD by biochemical analyses. These iPSCs-derived neuronal cells from GD3-1 and GD3-2 exhibit an impairment in endoplasmic reticulum (ER) calcium homeostasis and an increase in unfolded protein response markers (BiP and CHOP), indicating the presence of ER stress in nGD. A significant increase in the BAX/BCL-2 ratio and an increase in Annexin V-positive cells demonstrate a notable increase in apoptotic cell death in GD iPSCs-derived neurons, suggesting downstream signaling after an increase in the unfolded protein response. Our study involves the establishment of iPSCs-derived neuronal models for GD and proposes a possible mechanism underlying nGD. This mechanism involves the activation of ER stress and the unfolded protein response, ultimately leading to apoptotic cell death in neurons.

Establishment of MUi030-A: A human induced pluripotent stem cell line carrying homozygous L444P mutation in the GBA1 gene to study type-3 Gaucher disease

Gaucher disease (GD) is a common lysosomal storage disease resulting from mutations in the glucocerebrosidase (GBA1) gene. This genetic disorder manifests with symptoms affecting multiple organs, yet the underlying mechanisms leading to pathology remain elusive. In this study, we successfully generated the MUi030-A human induced pluripotent stem cell (hiPSC) line using a non-integration method from a male type-3 GD patient with a homozygous c.1448T>C (L444P) mutation. These hiPSCs displayed a normal karyotype and pluripotency markers and the remarkable ability to differentiate into cells representing all three germ layers. This resourceful model holds significant promise for illuminating GD's underlying pathogenesis.

Parental Awareness, Knowledge, and Attitudes Regarding Current and Future Newborn Bloodspot Screening: The First Report from Thailand

Newborn screening (NBS) is a public health service that is used to screen for treatable conditions in many countries, including Thailand. Several reports have revealed low levels of parental awareness and knowledge about NBS. Because of limited data on parental perspectives toward NBS in Asia and the differences in socio-cultural and economic contexts between Western and Asian countries, we conducted a study to explore parental perspectives on NBS in Thailand. A Thai questionnaire to assess awareness, knowledge, and attitudes regarding NBS was constructed. The final questionnaire was distributed to pregnant women, with or without their spouses, and to parents of children aged up to one year who visited the study sites in 2022. A total of 717 participants were enrolled. Up to 60% of parents were identified as having good awareness, which was significantly associated with gender, age, and occupation. Only 10% of parents were classified as having good knowledge relative to their education level and occupation. Providing appropriate NBS education should be initiated during antenatal care, focusing on both parents. This study noted a positive attitude toward expanded NBS for treatable inborn metabolic diseases, incurable disorders, and adult-onset diseases. However, modernized NBS should be holistically evaluated by multiple stakeholders in each country because of different socio-cultural and economic contexts.

Comprehensive and long-term outcomes of enzyme replacement therapy followed by stem cell transplantation in children with Gaucher disease type 1 and 3

BACKGROUND

Gaucher disease (GD) is a lysosomal storage disorder, characterized by hepatosplenomegaly, pancytopenia, bone diseases, with or without neurological symptoms. Plasma glucosylsphingosine (lyso-Gb1), a highly sensitive and specific biomarker for GD, has been used for diagnosis and monitoring the response to treatment. Enzyme replacement therapy (ERT) is an effective treatment for the non-neurologic symptoms of GD. Neuronopathic GD (type 2 and 3) accounts for 60%-70% of the Asian affected population.

METHODS

We explored combination therapy of ERT followed by hematopoietic stem cell transplantation (HSCT) and its long-term outcomes in patients with GD type 3 (GD3).

RESULTS

Four patients with GD3 and one with GD type 1 (GD1) underwent HSCT. The types of donor were one matched-related, one matched-unrelated, and three haploidentical. The age at disease onset was 6-18 months and the age at HSCT was 3.8-15 years in the patients with GD3. The latest age at follow-up was 8-22 years, with a post-HSCT duration of 3-14 years. All patients had successful HSCT. Chronic graft-versus-host disease occurred in one patient. The enzyme activities were normalized at 2 weeks post HSCT. Lyso-Gb1 concentrations became lower than the pathological value. All of the patients are still alive and physically independent. Most of them (4/5) returned to school. None of the patients with GD3 had seizures or additional neurological symptoms after HSCT, but showed varying degrees of cognitive impairment.

CONCLUSIONS

ERT followed by HSCT could be considered as an alternative treatment for patients with GD3 who have a high risk of fatal neurological progression.

Phenotypic and molecular features of Thai patients with primary carnitine deficiency

BACKGROUND

Primary carnitine deficiency (PCD) is screened by expanded newborn screening (NBS) using tandem mass spectrometry (MS/MS) that can detect both affected neonates and mothers. This study aimed to delineate the clinical, biochemical, and molecular findings of Thai PCD patients.

METHODS

Expanded NBS using MS/MS was implemented in Bangkok and 146,757 neonates were screened between 2014 and 2018. PCD was screened by low free carnitine (C0) levels in dried blood spots. Plasma C0 levels and C0 clearance values were measured in neonates and their mothers with positive screening results. Clinically diagnosed cases were described. The coding regions and intron-exon boundaries of the SLC22A5 gene were sequenced in all cases with low plasma C0 levels.

RESULTS

There were 14 cases with confirmed PCD: two clinically diagnosed cases, and 12 cases identified through NBS including five newborns, six mothers, and one older sibling. Thus, the incidence of PCD in neonates was 1:29,351. All affected neonates and mothers were asymptomatic except one mother with dilated cardiomyopathy. SLC22A5 gene sequencing identified biallelic causative variants in all cases, comprising 10 different variants of which four were novel. c.51C > G (p.Phe17Leu) and c.760C > T (p.Arg254Ter) were the most prevalent variants in this study. Cases with significant clinical features tended to have higher C0 clearance values.

CONCLUSIONS

Primary carnitine deficiency is a common inherited metabolic disorder (IMD) in Thailand. Our findings broaden the spectrum of SLC22A5 variants. The future national NBS program will shed more light on PCD and other IMDs in Thailand.

Central Precocious Puberty in a Boy with Pseudohypoparathyroidism Type 1A due to a Novel GNAS Variant, with Congenital Hypothyroidism as the First Manifestation

Pseudohypoparathyroidism (PHP) type 1A (PHP1A) is a disorder of multiple hormone resistance, mainly parathyroid hormone. It is associated with Albright hereditary osteodystrophy phenotypes. Patients with PHP1A may initially present with hypothyroidism during infancy and later develop typical PHP1A characteristics during their childhood. Central precocious puberty (CPP) is extremely rare among PHP1A patients in whom gonadotropin resistance is more usual. This is a case report of a 9.5-year-old boy with congenital hypothyroidism who developed hypocalcemia secondary to PHP. He had relatively short stature with height standard deviation score of -0.9. Obesity had been noted since the age of two years. At the presentation of PHP, pubertal-sized testes of 10 mL were observed, and CPP was documented with serum testosterone concentration of 298 ng/dL (normal for Tanner stage III, 100-320), luteinizing hormone of 3.9 IU/L (normal, 0.2-5.0), and follicle stimulating hormone of 4.8 IU/L (normal, 1.2-5.8). Pituitary magnetic resonance imaging was unremarkable. Genetic analysis confirmed the diagnosis of PHP1A with a novel heterozygous missense variant of GNAS gene in exon 13, c.1103A>G (p.Asp368Gly). Awareness of PHP1A diagnosis in patients with congenital hypothyroidism and early childhood-onset obesity is important for early diagnosis. Apart from multiple hormone resistance, CPP may manifest in patients with PHP1A.

A novel TCN2 mutation with unusual clinical manifestations of hemolytic crisis and unexplained metabolic acidosis: expanding the genotype and phenotype of transcobalamin II deficiency

Background

Transcobalamin deficiency is a rare inborn metabolic disorder, characterized by pancytopenia, megaloblastic anemia, failure to thrive, diarrhea, and psychomotor retardation.

Case presentation

We describe a patient who first presented at 3 months of age, with pancytopenia, hepatosplenomegaly, recurrent infection, metabolic acidosis, and acute hemolytic crisis. Extensive hematologic and immunologic investigations did not identify inherited bone marrow failure syndrome, acute leukemia or its related disorders. Whole exome sequencing identified a novel homozygous TCN2 mutation, c.428-2A > G and mRNA study confirmed an aberrant transcription of exon 4 skipping. The mutant protein is predicted to have an in-fame 51 amino acids deletion (NP_000346:p.Gly143_Val193del). The patient exhibited marked clinical improvement following hydroxocobalamin treatment.

Conclusions

Transcobalamin deficiency should be investigated in infants with unexplained pancytopenia and acute hemolytic crisis with or without typical evidence of vitamin B12 deficiency.

Sleep Disorder: An Overlooked Manifestation of Glucose Transporter Type-1 Deficiency Syndrome

Glucose transporter type-1 deficiency syndrome (Glut1 DS) is a rare disorder with various manifestations. Early diagnosis is crucial because treatment with the ketogenic diet can lead to clinical improvement. Here, we report the cases of two siblings with Glut1 DS and one of them presented with sleep disorder which is a rare and atypical manifestation of Glut1 DS. Patient 1 was a 3.5-year-old boy who presented with paroxysmal loss of tone and weakness of the whole body with unresponsiveness after waking up. He also had excessive daytime sleepiness, insomnia, and restless sleep. His other clinical findings included focal seizures, paroxysmal exercise-induced dyskinesia (PED), ataxia, mild global developmental delay, and hyperactivity. Patient 2 was a 5.5-year-old boy who presented with drug-resistant focal epilepsy, global developmental delay, paroxysmal dystonia, and ataxia. A novel heterozygous nonsense variant of SLC2A1, c.1177G > T (p.Glu393*), classified as a pathogenic variant, was identified in both patients, but not in their parents' blood. After treatment with the modified Atkins diet, their neurological functions significantly improved. In conclusion, we reported two siblings with variable phenotypes of Glut1 DS with a novel nonsense mutation. Although sleep disorder and daytime somnolence were the nonclassical manifestations of Glut1 DS, the diagnostic evaluation of possible Glut1 DS in patients presented with daytime sleepiness, particularly in cases with the cooccurrence of seizures or movement disorders should be considered.

Epidermolysis Bullosa With Congenital Absence of Skin: Congenital Corneal Cloudiness and Esophagogastric Obstruction Including Extended Genotypic Spectrum of PLEC, LAMC2, ITGB4 and COL7A1

Epidermolysis bullosa (EB) is a rare and genetically heterogeneous disorder characterized by skin fragility and blister formation occurring spontaneously or after minor trauma. EB is accompanied by congenital absence of skin (EB with CAS) in some patients. Pathogenic variants of COL7A1 are responsible for EB with CAS in the vast majority of cases. Type and subtype diagnosis of EB with CAS generally requires specific immunohistological examinations that are not widely available plus targeted gene analysis. The present study aimed to determine the clinical features of five patients affected by EB with CAS and to identify the underlying genetic defects using whole exome sequencing (WES) followed by focused analysis of the target genes. Four patients had generalized skin involvement and one had localized defects. Two patients exhibited extremely severe skin manifestations and congenital cloudy cornea along with pyloric atresia, and one had partial esophagogastric obstruction and anuria due to vesicoureteric obstruction. In the WES analysis, the average coverage of the target exons was 99.05% (726 of 733 exons), with a range of 96.4–100% for individual genes. We identified four novel and two known pathogenic/likely pathogenic variants of five distinct genes in the examined families: PLEC:c.2536G > T (p.Glu846Ter); LAMC2:c.3385C > T (p.Arg1129Ter); KRT5:c.429G > A (p.Glu477Lys); ITGB4:c.794dupC (p.Ala266SerfsTer5); COL7A1:c.5440C > T (p.Arg1814Cys); and COL7A1:c.6103delG. All alleles were inherited from the parents, except for the KRT5 variant as a de novo finding. The findings reveal extremely rare phenotypes found in EB with CAS, namely congenital cloudy cornea, esophagogastric obstruction, and anuria, and extend the genotypic spectrum of EB-related genes. The data confirm that WES provides very high coverage of coding exons/genes and support its use as a reasonable alternative method for diagnosis of EB. The present data from an underrepresented population in Southeast Asia could further broaden the knowledge and research on EB.

Etiology and outcome of acute recurrent pancreatitis and chronic pancreatitis

BACKGROUND

Owing to the lack of data, we aimed to determine the etiology and outcome of acute recurrent pancreatitis (ARP) and chronic pancreatitis (CP) in children in Southeast Asia.

METHODS

This retrospective study was conducted at a university hospital in Bangkok, Thailand. We included patients aged <18 years who were diagnosed with pancreatitis from 2000 to 2021.

RESULTS

Among 155 patients with pancreatitis, 21 (13.5%) were diagnosed with either ARP (n = 7) or CP (n = 14). Clinical manifestations of CP included chronic abdominal pain (n = 10, 71.4%), steatorrhea (n = 8, 57.1%), and diabetes mellitus (n = 1, 7.1%). Positive radiological findings compatible with CP were detected from an abdominal ultrasound, computed tomography, magnetic resonance cholangiopancreatography in 70%, 90.9%, and 92.9% of patients, respectively. Genetic, metabolic, and pancreaticobiliary causes were the major causes of ARP/CP (23.8% each) and the etiologies were unidentified in one-fifth of the patients. Patients with metabolic diseases who had AP were at-risk of developing ARP (hazards ratio [HR], 4.7, 95% confidence interval [CI]: 1.5-13.9). Children with ARP or CP were younger than those with AP (P = 0.04). Approximately two-thirds of patients with CP had growth faltering and they had more episodes of hospitalization due to acute attacks when compared to patients with ARP ( 4 [interquartile range [IQR], 3-6] vs. 3 [IQR, 2-3]; P = 0.02).

CONCLUSION

Genetic, metabolic, and pancreaticobiliary diseases were the common etiologies of ARP and CP among children living in a developing country in Southeast Asia. The burden of CP included malnutrition and frequent hospitalization. The findings emphasize the importance of an early etiological diagnosis and monitoring for pancreatic insufficiency in ARP/CP.

Association of Mitochondrial DNA Polymorphisms With Pediatric-Onset Cyclic Vomiting Syndrome

BACKGROUND

Cyclic vomiting syndrome (CVS) is a functional gastrointestinal disorder characterized by recurrent stereotypic episodes of vomiting. The pathophysiology of CVS remains obscure. Previous studies have supported the hypotheses of mitochondrial dysfunction. However, data on association studies between mitochondrial DNA (mtDNA) polymorphisms and pediatric-onset CVS are limited and inconsistent. The aims of this study were to describe clinical characteristics, evaluate association of mtDNA polymorphisms 16519T and 3010A with pediatric-onset CVS and identify new mtDNA candidate variants.

METHODS

This study involved Thai patients diagnosed with CVS according to the Rome III or IV criteria before the age of 15 years. Patients' demographic data, clinical characteristics, previous investigations and treatment outcomes were obtained. Blood samples were collected for next-generation (whole exome) sequencing, followed by analysis of chromosome M (mitochondrial. Variants were filtered according to clinical significance using ClinVar and MITOMAP. mtDNA polymorphisms in 148 normal Thai individuals were used as controls.

RESULTS

Forty-eight children were enrolled in the clinical study, and 30 participated in the genetic analysis. The median age at onset and median age at diagnosis was 3.0 (1.5-5.6) and 6.3 (3.0-8.6) years, respectively. Maternal history of migraine was positive in 16.7%. About 45.7% (21 of 46) of the patients achieved complete clinical remission, with the mean symptom duration of 5.9 ± 3.3 years. The prevalence of mtDNA variants 16519T and 3010A among the patient group and Thai general population (control) were as follows: 40.0% (12/30) vs. 27.7% (P = 0.18) and 6.7% (2/30) vs. 0.7% (P = 0.07), respectively. Five known pathogenic variants were identified in 6 patients, including mtDNA 8528C in one patient who also had infantile hypertrophic cardiomyopathy. Six likely pathogenic variants were found but without statistical significance. We identified 11 variants with significant prevalence in the patient group. Though, these variants were classified as variants of unknown significance (VUS), several of them were located in mt functional regions and therefore they deserve further investigations as new candidates for association with pediatric CVS.

CONCLUSION

There were no associations of mtDNA polymorphisms 16519T and 3010A with CVS in our pediatric cohort. Five pathogenic variants and 11 VUS were found associated with pediatric-onset CVS.

Gaucher disease: clinical phenotypes and refining GBA mutational spectrum in Thai patients

BACKGROUND

Gaucher disease (GD) is a rare lysosomal storage disorder, characterized by hepatosplenomegaly and pancytopenia, with or without neurologic involvement. The disorder is categorized into three phenotypes: GD type 1 or nonneuronopathic GD; GD type 2 or acute neuronopathic GD; and GD type 3 or chronic neuronopathic GD. The purposes of this study were to describe clinical characteristics of Thai GD in patients diagnosed and/or followed up during 2010-2018 and to perform re-genotyping including analysis of GBA recombinant alleles which had not been investigated in Thai patients before.

RESULTS

There were 27 patients from seven medical centers, enrolled in the study. All the cases had pediatric onset. GD3 (44.5%) was the most common phenotype, followed by GD2 (40.7%) and GD1 (14.8%), with one case of neonatal GD. The median age of onset for GD1, GD2, and GD3 was 72, 4 and 12 months, respectively, suggesting relatively earlier onset of GD1 and GD3 in Thai patients. All patients with GD1 and most patients with GD3 received ERT. Four patients with GD3 had ERT followed by HSCT. Patients with GD3 who received no or late ERT showed unfavorable outcomes. We identified 14 variants including two novel (p.S384F and p.W533*) and 12 reported pathogenic variants: p.L483P, p.N409S, p.R159W, p.P305A, p.A175G, p.D448H, p.V414L, IVS2+1G>A, IVS6-1G>C, IVS7+1G>C, IVS9-3C>G, and Rec1a. The p.L483P was the most prevalent allele found in this study, at 66% (33/50 alleles), followed by IVS2+1G>A, Rec1a, and IVS6-1G>C. Twenty-four percent of patients were reassigned with validated genotypes, most of whom (4 of 6) were patients with GD2. The [p.S384F + p.W533*] being compounded with p.L483P, was found in the patient with neonatal GD, suggesting that the p.S384F could potentiate the deleterious effect of the p.W533*, and/or vice versa.

CONCLUSIONS

Neuronopathic GD was strikingly prevalent among Thai affected population. Homozygous p.L483P was the most common genotype identified in Thai patients. Recombinant allele Rec1a and splicing mutations were associated with GD2 and severe cases of GD3. Mutation spectrum could be useful for designing stepwise molecular analysis, genetic screenings in population, and new therapeutic research for neuronopathic GD.

Comparison of 24-Hour Recall and 3-Day Food Records during the Complementary Feeding Period in Thai Infants and Evaluation of Plasma Amino Acids as Markers of Protein Intake

Background: An accurate and reliable measurement of nutrient intake is the first and foremost step in order to optimise infant nutrition and evaluate its impact on health outcomes. However, research on the validity of dietary assessment tools used during the weaning period is limited, especially in lower-middle income countries. The primary aim of this study was to evaluate relative validity of a 24-h recall method (24-HR) using a 3-day food record (3-DFR). A secondary aim was to investigate association between protein intake from 3-DFR and plasma amino acids as a potential protein biomarker. Methods A multicentre, prospective cohort study was conducted in Chiang Mai, Thailand from June 2018 to May 2019. Food consumption data were collected in healthy infants using 24-HR and 3-DFR at 9 and 12 months of age. Blood samples were obtained at 12 months (M). Plasma amino acids were analysed using high performance liquid chromatography. Results Of 145 infants, 49% were female. At group level, paired t-tests/Wilcoxon signed rank tests did not show significant differences between average nutrient intakes from the 2 dietary assessment methods, except for vitamin A and vitamin C. Weighted kappa (Kw) was acceptable for all nutrients, except for vitamin A intake at 9 M (Kw = 0.15). The Bland–Altman analyses were unbiased for most nutrients with variable limits of agreement. At individual level, correlation coefficients (r) ranged from acceptable to excellent (r = 0.37–0.87) while cross-classifications showed acceptable outcomes, except for vitamin A. Multivariate analyses showed significant associations between protein intake at 12 M from the 3-DFR and plasma concentrations of branched-chain amino acids (BCAA) and essential amino acids (EAA), even after adjusting for gender, milk feeding type and energy intake. Conclusions For infants aged 9–12 M, a 24-HR can be used as a more practical alternative to a 3-DFR for most nutrients although caution is required for some micronutrients, especially vitamin A. A repeated interview might further improve the accuracy. Furthermore, protein intake, particularly animal-based protein, significantly predicted plasma BCAA and EAA concentrations regardless of gender, type of milk feeding and energy consumption.

Novel SOX10 Mutations in Waardenburg Syndrome: Functional Characterization and Genotype-Phenotype Analysis

Waardenburg syndrome (WS) is a prevalent hearing loss syndrome, concomitant with focal skin pigmentation abnormalities, blue iris, and other abnormalities of neural crest-derived cells, including Hirschsprung’s disease. WS is clinically and genetically heterogeneous and it is classified into four major types WS type I, II, III, and IV (WS1, WS2, WS3, and WS4). WS1 and WS3 have the presence of dystopia canthorum, while WS3 also has upper limb anomalies. WS2 and WS4 do not have the dystopia canthorum, but the presence of Hirschsprung’s disease indicates WS4. There is a more severe subtype of WS4 with peripheral nerve and/or central nervous system involvement, namely peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, WS, and Hirschsprung’s disease or PCW/PCWH. We characterized the genetic defects underlying WS2, WS4, and the WS4-PCW/PCWH) using Sanger and whole-exome sequencing and cytogenomic microarray in seven patients from six unrelated families, including two with WS2 and five with WS4. We also performed multiple functional studies and analyzed genotype–phenotype correlations. The cohort included a relatively high frequency (80%) of individuals with neurological variants of WS4. Six novel SOX10 mutations were identified, including c.89C > A (p.Ser30^∗), c.207_8 delCG (p.Cys71Hisfs^∗62), c.479T > C (p.Leu160Pro), c.1379 delA (p.Tyr460Leufs^∗42), c.425G > C (p.Trp142Ser), and a 20-nucleotide insertion, c.1155_1174dupGCCCCACTATGGCTCAGCCT (p.Phe392Cysfs^∗117). All pathogenic variants were de novo. The results of reporter assays, western blotting, immunofluorescence, and molecular modeling supported the deleterious effects of the identified mutations and their correlations with phenotypic severity. The prediction of genotype–phenotype correlation and functional pathology, and dominant negative effect vs. haploinsufficiency in SOX10-related WS were influenced not only by site (first two vs. last coding exons) and type of mutation (missense vs. truncation/frameshift), but also by the protein expression level, molecular weight, and amino acid content of the altered protein. This in vitro analysis of SOX10 mutations thus provides a deeper understanding of the mechanisms resulting in specific WS subtypes and allows better prediction of the phenotypic manifestations, though it may not be always applicable to in vivo findings without further investigations.

DUOX2 variants are a frequent cause of congenital primary hypothyroidism in Thai patients

OBJECTIVE

To identify the genetic etiologies of congenital primary hypothyroidism (CH) in Thai patients.

DESIGN AND METHODS

CH patients were enrolled. Clinical characteristics including age, signs and symptoms of CH, pedigree, family history, screened thyroid-stimulating hormone results, thyroid function tests, thyroid imaging, clinical course and treatment of CH were collected. Clinical exome sequencing by next-generation sequencing was performed. In-house gene list which covered 62 potential candidate genes related to CH and thyroid disorders was developed for targeted sequencing. Sanger sequencing was performed to validate the candidate variants. Thyroid function tests were determined in the heterozygous parents who carried the same DUOX2 or DUOXA2 variants as their offsprings.

RESULTS

There were 118 patients (63 males) included. Mean (SD) age at enrollment was 12.4 (7.9) years. Forty-five of 118 patients (38%) had disease-causing variants. Of 45 variants, 7 genes were involved (DUOX2, DUOXA2, TG, TPO, SLC5A5, PAX8 and TSHR). DUOX2, a gene causing thyroid dyshormonogenesis, was the most common defective gene (25/45, 56%). The most common DUOX2 variant found in this study was c.1588A>T. TG and TPO variants were less common. Fourteen novel variants were found. Thyroid function tests of most parents with heterozygous state of DUOX2 and DUOXA2 variants were normal.

CONCLUSIONS

DUOX2 variants were most common among Thai CH patients, while TG and TPO variants were less common. The c.1588A>T in DUOX2 gene was highly frequent in this population.

Etiologies, Prognostic Factors, and Outcomes of Pediatric Acute Liver Failure in Thailand

PURPOSE

Pediatric acute liver failure (PALF) is a serious condition; however, data on PALF in developing countries are sparse, particularly concerning molecular diagnosis and liver transplantation (LT). This study aimed to determine the causes, outcomes, and prognostic factors of PALF.

METHODS

We retrospectively reviewed the medical records of children (age <15 years) with PALF diagnosed using the American Association for the Study of Liver Diseases criteria at our center from 2011 to 2016. The collected data included laboratory results, complications, outcomes, and potential factors associated with death and LT.

RESULTS

We included a total of 27 patients, with a median age of 2 years (interquartile range, 3 months to 4 years). Viral infection was the most common etiology (n=8, 30%), predominantly dengue infection (n=4). A total of 16 patients (59%) died and 11 patients survived (3 patients with LT). The prognostic factors associated with death or LT requirement were grade IV hepatic encephalopathy (p<0.01), hypotension (p=0.02), gastrointestinal bleeding (p=0.03), increased intracranial pressure (p=0.04), and higher peak serum lactate level (p=0.01). Peak serum lactate ≥6 mmoL/L had a sensitivity of 79% and a specificity of 88% for predicting mortality or the necessity of LT.

CONCLUSION

Viral infection was the most common cause of PALF. The mortality rate remained high, and a considerable number of patients required LT. In addition to several clinical factors, peak serum lactate could be a potential marker for predicting poor outcomes in PALF.

Klinefelter Syndrome Mosaicism 46,XX/47,XXY: A New Case and Literature Review

Most cases of Klinefelter syndrome (KS) have 47,XXY karyotype. We reported the first case of 46,XX/47,XXY KS whose genital ambiguity was detected prenatally with postnatal confirmation of the mosaicism and ovotesticular disorder of sex development (OT-DSD). The paternal origin of the extra X chromosome was identified using trio cytogenomic single-nucleotide polymorphism array. Additional 18 cases were also reviewed. The clinical presentation of 46,XX/47,XXY is age-dependent with two age peaks, including ambiguous genitalia during infancy and gynecomastia with or without cyclical hematuria and left scrotal pain and mass in adolescence. The 46,XX is the predominant karyotype both in peripheral blood and gonadal tissue. The risk of germ cell tumor is very high throughout life in these individuals. Individuals with 46,XX/47,XXY mosaicism should be treated more as OT-DSD other than a simple mosaic KS. A multidisciplinary approach and long-term monitoring are necessary.

Kabuki syndrome with midgut malrotation and hyperinsulinemic hypoglycemia: A rare co-occurrence from Thailand

Kabuki syndrome (KS) is a rare heterogeneous phenotypic genetic syndrome, characterized by hypotonia, developmental delay and/or intellectual disability with typical facial features. It is challenging to diagnose KS in newborn and young infant. We report a Thai girl who presented with two rare co-occurrence phenotypes, hyperinsulinemic hypoglycemia and midgut malrotation. She had not have distinctive facial dysmorphism during neonatal period. At 4 months of age, she had poor weight gain with some facial features suggestive KS. Singleton whole exome sequencing (WES) was carried out followed by Sanger sequencing of the supposed variant. The result indicated a novel de novo heterozygous KMT2D mutation, c.15364A>T (p.Lys5122*), confirming KS. Our patient revealed rare clinical manifestations from the diverse population and address the benefit of WES in establishing early diagnosis of KS before typical facial gestalt exhibited, which allows timely and appropriate management to maximize developmental achievement.

Growth charts for Thai children with Prader-Willi syndrome aged 0-18 years

BACKGROUND

Prader-Willi syndrome (PWS) is a multisystem genetic disorder, which has a typical eating behavior and growth pattern. In the infancy period, children with PWS have low body weight followed by hyperphagia in later childhood. Disease-specific growth charts have been recommended for monitoring PWS patients. Previous literature demonstrated growth differences among individuals with PWS of different ethnicity.

METHODS

A retrospective multicenter study was performed in PWS patients from different areas of Thailand included collaboration with the Thai PWS support group during 2000-2017. Baseline characteristics and anthropometric data were reviewed. Both growth hormone and non-growth hormone received patients were included, but the data after receiving GH were excluded before curve construction. Growth charts for Thai PWS compared to the 50th normative centile were constructed using Generalized Least Squares (GLS) methods. Curve smoothing was performed by Fractional Polynomials and Exponential Transformation.

RESULT

One hundred and thirteen patients with genetically confirmed PWS (55 males and 58 females) were enrolled. Fifty percent of patients were diagnosed less than 6 months of age. We developed growth charts for non-growth hormone treated Thai children with PWS aged between 0 and 18 years. A growth pattern was similar to other ethnicities while there were some differences. Mean birth weight of PWS patients was less than that of typical newborns. Mean adult height at 18 years of age in Thai children with PWS was lower than that in American children, but taller than Japanese. Mean weight of Thai PWS males at 18 years of age was more than those from other countries.

CONCLUSION

This study is the first to document PWS-specific growth charts in Southeast Asian population. These growth charts will be useful in improving the quality of patient care and in evaluating the impact of growth hormone treatment in the future.

Clinical course, mutations and its functional characteristics of infantile-onset Pompe disease in Thailand

Background

Pompe disease is a lysosomal storage disorder caused by the deficiency of acid alpha-glucosidase (EC. 3.2.1.20) due to mutations in human GAA gene. The objective of the present study was to examine clinical and molecular characteristics of infantile-onset Pompe disease (IOPD) in Thailand.

Methods

Twelve patients with infantile-onset Pompe disease (IOPD) including 10 Thai and two other Asian ethnicities were enrolled. To examine the molecular characteristics of Pompe patients, GAA gene was analyzed by PCR amplification and direct Sanger-sequencing of 20 exons coding region. The novel mutations were transiently transfected in COS-7 cells for functional verification. The severity of the mutation was rated by study of the GAA enzyme activity detected in transfected cells and culture media, as well as the quantity and quality of the proper sized GAA protein demonstrated by western blot analysis. The GAA three dimensional structures were visualized by PyMol software tool.

Results

All patients had hypertrophic cardiomyopathy, generalized muscle weakness, and undetectable or < 1% of GAA normal activity. Three patients received enzyme replacement therapy with variable outcome depending on the age of the start of enzyme replacement therapy (ERT). Seventeen pathogenic mutations including four novel variants: c.876C > G (p.Tyr292X), c.1226insG (p.Asp409GlyfsX95), c.1538G > A (p.Asp513Gly), c.1895 T > G (p.Leu632Arg), and a previously reported rare allele of unknown significance: c.781G > A (p.Ala261Thr) were identified. The rating system ranked p.Tyr292X, p. Asp513Gly and p. Leu632Arg as class “B” and p. Ala261Thr as class “D” or “E”. These novel mutations were located in the N-terminal beta-sheet domain and the catalytic domain.

Conclusions

The present study provides useful information on the mutations of GAA gene in the underrepresented population of Asia which are more diverse than previously described and showing the hotspots in exons 14 and 5, accounting for 62% of mutant alleles. Almost all mutations identified are in class A/B. These data can benefit rapid molecular diagnosis of IOPD and severity rating of the mutations can serve as a partial substitute for cross reactive immunological material (CRIM) study.

Perspectives of adults with Klinefelter syndrome, unaffected adolescent males, and parents of affected children toward diagnosis disclosure: a Thai experience

Little is known about disclosure of diagnosis to males with Klinefelter syndrome (KS) diagnosed before birth or during childhood, especially in Asian context. Insufficient preparation for disclosure communication could lead to the child's depression, anxiety, or disrupted self-esteem. This is an interventional and qualitative interview study with a brief self-reported survey. The study consists of three phases. In phase I, adults with KS were asked about their experiences and viewpoints toward KS disclosure and diagnosis through individual interviews. In phase II, unaffected adolescent males were given information about KS and then asked to give hypothetical answers to a questionnaire followed by a group interview, as if they had KS. In phase III, parents of children with KS were asked to complete a questionnaire followed by a group interview which included a discussion about their disclosure plans and their concerns. The parents were provided information obtained from adults with KS and unaffected adolescent males, and were then interviewed again as a group. We found that the most hurtful issues were discovering their infertility from KS and late disclosure. From the perspective of unaffected adolescent males, early disclosure in early or mid-teens in a neutral, supportive, and relaxed manner, along with information on benefits of hormonal treatment, the assurance of biological sex as "male," and avoidance of some sensitive words are strongly recommended, as a way to promote self-confidence and positive coping with the diagnosis. After intervention, the parents reported more confidence and less anxiety about disclosing the diagnosis to their children, and indicated that they would disclose KS at an earlier age. For unaffected adolescent males, though it is a hypothetical scenario and their reaction may differ from affected adolescents, unaffected adolescent males' viewpoints on how they might react are more or less representative of cultural changes for the new generation, especially in the Asian context. In addition, their viewpoints influenced parents' decision and genetic counseling plans for the diagnosis disclosure of KS to their children. We propose a preliminary guideline for KS diagnosis disclosure.

Clinical delineation of 18q11-q12 microdeletion: Intellectual disability, speech and behavioral disorders, and conotruncal heart defects

Background

Since the establishment of chromosomal microarrays in clinical practice, many new microdeletion/microduplication syndromes have been identified, including 18q11.2 microdeletion. Chromosome 18q deletion syndrome is commonly classified into distal deletion and a much rarer proximal interstitial deletion spanning the 18q11.2‐q21.1 region.

Methods

We report two new patients and review 27 additional cases in DECIPHER/ClinGen databases and four cases from the literature, with more proximal 18q deletions involving 18q11‐q12 (band 1 only; 17.2–43.5 Mb position) deletion.

Results

Common presentations of 18q11‐q12 deletions include developmental delay/intellectual disability (DD/ID) (82%); speech delay/autism/attention deficit and hyperactivity/other behavioral problems (30%); conotruncal heart defects (15%); and subtle/non‐specific facial dysmorphism. The deletion in four out of five cases with cardiac defect was distal to GATA6, suggesting an alternative mechanism other than haploinsufficiency of GATA6 as an underlying cause of cardiac malformations. Precocious puberty with advanced skeletal age was first observed in one patient, suggesting a unique and expanded phenotype of proximal 18q deletion. When comparing genotype–phenotype correlations from the present study with previous reports, the critical regions for selected phenotypes of 18q11‐q12 deletion syndrome could be narrowed down as follows: 38.8–43.5 Mb for moderate to severe DD/ID, 19.6–24.4 Mb and 26.9–28.6 Mb for conotruncal heart defect.

Conclusion

The detailed clinical delineation of the proximal 18q deletions identified in this study should contribute to better understanding of the genotype–phenotype correlations and better long‐term care of patients with this rare syndrome.

p.X654R IDUA variant among Thai individuals with intermediate mucopolysaccharidosis type I and its residual activity as demonstrated in COS-7 cells

BACKGROUND

Mucopolysaccharidosis type I (MPS I) is a rare autosomal-recessive disorder caused by defects in alpha-L-iduronidase (IDUA), a lysosomal enzyme encoded by the IDUA gene. Herein, we characterized IDUA mutations underlying mucopolysaccharidosis type I intermediate form (Hurler-Scheie syndrome) and its molecular pathogenic mechanisms.

METHODS

Clinical data, activity of the IDUA enzyme in leukocytes, and a mutation of the IDUA gene were analyzed. Pathogenesis associated with an IDUA mutation was further investigated by evaluating the mutant cDNA sequence, protein expression and activity in COS-7 cells.

RESULTS

Five unrelated patients were identified to have clinical diagnosis of intermediate form of MPS I (Hurler-Scheie) and exhibited low-to-absent levels of leukocyte IDUA activity. Genetic analysis revealed homozygous c.*1T>C (p.X654R) mutation in two patients and compound heterozygosity between the c.*1T>C and another allele including c.265G>A (p.R89Q), c.935G>A (p.W312X), or c.1138 C>T (p.Q380X), each in a single patient. Sequencing the 3'RACE product of the c.*1T>C (p.X654R) allele indicated a 38-amino acids elongation of the mutant protein. COS-7 cells expressing IDUA with the mutations exhibited extremely low levels or complete absence of enzyme activity compared to wild-type IDUA. Western blot analysis detected no protein in p.W312X and p.Q380X samples, while an elevated molecular mass and a different pattern of protein bands were found in p.X654R specimen compared with the wild type IDUA.

CONCLUSIONS

Mutational spectrum underlying intermediate MPS I is expanded. Our data suggest that the p.X654R is an intermediate IDUA mutant allele with residual enzyme activity. It can lead to intermediate or milder form of MPS I depending on another associated allele.

1q21.3 deletion involving GATAD2B: An emerging recurrent microdeletion syndrome

GATAD2B gene is involved in chromatin modification and transcription activity. Loss-of-function mutations of GATAD2B have recently been defined to cause a recognizable syndrome with intellectual disability (ID). Human TPM3 gene encoding thin filament protein is associated with myopathies. Both genes are located on chromosome 1q21.3. We herein report an infant with feeding difficulty, developmental delay, hypotonia, and dysmorphic features including small palpebral fissures, telecanthus, sparse hair and eyebrow, cup-shaped ears, and clinodactyly. Karyotype was normal. Single nucleotide polymorphism array revealed a 1.06 Mb deletion of chromosome 1q21.3, which was confirmed to be de novo. The deleted region encompassed 35 genes, including three known disease-associated genes, namely GATAD2B, TPM3, and HAX1. We further identify and summarize seven additional patients with 1q21.3 microdeletion from literature review and clinical databases (DECIPHER, ISCA/ClinGen). Genomic location analysis of all eight patients revealed different breakpoints and no segmental duplication, indicating that non-homologous end joining is a likely mechanism underlying this particular microdeletion. This data suggests that 1q21.3 microdeletion is a recurrent microdeletion syndrome with distinguishable phenotypes, and loss of function of GATAD2B is the major contributor of the characteristic facies and ID. Additionally, the deletion of TPM3 warrants a risk of concomitant muscle disease in our patient. © 2017 Wiley Periodicals, Inc.

Chromosomal microarray analysis in a cohort of underrepresented population identifies SERINC2 as a novel candidate gene for autism spectrum disorder

Chromosomal microarray (CMA) is now recognized as the first-tier genetic test for detection of copy number variations (CNVs) in patients with autism spectrum disorder (ASD). The aims of this study were to identify known and novel ASD associated-CNVs and to evaluate the diagnostic yield of CMA in Thai patients with ASD. The Infinium CytoSNP-850K BeadChip was used to detect CNVs in 114 Thai patients comprised of 68 retrospective ASD patients (group 1) with the use of CMA as a second line test and 46 prospective ASD and developmental delay patients (group 2) with the use of CMA as the first-tier test. We identified 7 (6.1%) pathogenic CNVs and 22 (19.3%) variants of uncertain clinical significance (VOUS). A total of 29 patients with pathogenic CNVs and VOUS were found in 22% (15/68) and 30.4% (14/46) of the patients in groups 1 and 2, respectively. The difference in detected CNV frequencies between the 2 groups was not statistically significant (Chi square = 1.02, df = 1, P = 0.31). In addition, we propose one novel ASD candidate gene, SERINC2, which warrants further investigation. Our findings provide supportive evidence that CMA studies using population-specific reference databases in underrepresented populations are useful for identification of novel candidate genes.

Molecular analysis of the novel IDS allele in a Thai family with mucopolysaccharidosis type II: The c.928C>T (p.Gln310*) transcript is sensitive to nonsense-mediated mRNA decay

Hunter syndrome (or mucopolysaccharidosis type II, MPS II) is an X-linked recessive disorder induced by a deficiency of the iduronate 2-sulfatase (IDS) enzyme, resulting in the accumulation of glycosaminoglycan substrates, heparan sulfate and dermatan sulfate, in the lysosomes. The progressive accumulation of undegraded metabolites induces cell and tissue dysfunction, leading to multi-systemic pathology. The heterogeneity of clinical phenotypes, ranging from mild to severe forms, results from different mutations in the IDS gene. To date, >550 MPS II causal mutations have been reported in the IDS gene, of which ~10% are nonsense mutations that lead to premature protein termination. In the present study, the IDS mutation causing MPS II in an extended Thai family was identified using IDS enzyme assay and IDS gene exon sequencing. Three family members were enzymatically confirmed to have MPS II and to carry the novel IDS nonsense allele c.928C>T (p.Gln310*). The IDS mRNA levels were evaluated by reverse transcription-quantitative polymerase chain reaction, which demonstrated that all patients exhibited a reduction of IDS mRNA, suggesting its degradation by nonsense-mediated mRNA decay. Expression of wild type and mutant IDS in COS-7 cells revealed that the IDS p.Gln310* mutant lacked IDS activity, consistent with production of a nonfunctional, prematurely truncated protein. Taken together, these results indicate that the IDS c.928C>T (p.Gln310*) mutation is a severe disease-causing mutation for MPS II.

Clinical improvement of renal amyloidosis in a patient with systemic-onset juvenile idiopathic arthritis who received tocilizumab treatment: a case report and literature review

BACKGROUND

Juvenile idiopathic arthritis (JIA) is a common rheumatic disease in children and adolescents. Although JIA may cause secondary amyloidosis, this is a rare complication in patients with JIA and other rheumatic diseases. Many previous studies have revealed that common heterozygous or homozygous mutations in the MEFV gene are associated with systemic-onset JIA (SJIA).

CASE PRESENTATION

We herein report a case involving a 19-year-old female patient with difficult-to-control SJIA. She developed progressive proteinuria without clinical signs or symptoms of edema. Renal amyloidosis was diagnosed by renal pathologic examination, which demonstrated deposition of eosinophilic amorphous material in the interlobular arteries, arterioles, and interstitium. Electron microscopy showed fibrillary material deposits with a diameter of 8 to 10 nm. A heterozygous E148Q mutation in the MEFV gene was identified. Conventional disease-modifying anti-rheumatic drugs and etanercept had been used to treat the SJIA, but the disease could not be controlled. Therefore, we decided to start tocilizumab to control the disease activity. However, the patient was unable to receive a standard dose of tocilizumab in the early period of treatment because of socioeconomic limitations. Her disease course was still active, and proteinuria was found. Therefore, tocilizumab was increased to a dose of 8 mg/kg every 2 weeks (standard dose of SJIA), and the patient exhibited a clinical response within 3 months.

CONCLUSION

Refractory SJIA associated with renal amyloidosis is an uncommon cause of proteinuria in adolescents. Tocilizumab may be a beneficial treatment for renal amyloidosis in patients with SJIA.

Stopping Parenteral Nutrition for 3 Hours Reduces False Positives in Newborn Screening

OBJECTIVE

To evaluate effects of holding parenteral nutrition (PN) for 3 hours prior to newborn screening (NBS) on false-positive NBS rate for amino acids (AAs) in very low birth weight (VLBW) infants (birth weight <1500 g).

STUDY DESIGN

We analyzed data from 12 567 consecutive births in 1 hospital between May 2010 and June 2013. VLBW infants were stratified into 3 groups: (1) infants without PN before NBS (no-PN group); (2) infants with early PN running at the time of NBS (early-PN group); and (3) infants with early-PN that were temporarily replaced by dextrose-containing intravenous fluid 3 hours prior to NBS (stop-PN group). We compared the false-positive rate for AA and cost effectiveness between the groups.

RESULTS

The false-positive rate for AA among 413 VLBW infants was significantly higher than infants with birth weight >1500 g (7.62% vs 0.05%; P < .001). There were no false-positive results for AA in the no-PN group. The false-positive rate for AA in the stop-PN group (2/65) was significantly lower than the early-PN group (29/245) (3.1% vs 11.8%; P = .037). The stop-PN group was more cost effective than early-PN group, saving $17.27 per infant screened ($5.53 vs $22.80) or $192.54 for each false-positive result for AA averted. Further reductions in inconclusive samples were also noted.

CONCLUSIONS

VLBW and early-PN are significant factors for false-positive results for AA. Holding PN containing AAs for 3 hours before NBS collection is a practical and cost-effective method to significantly reduce the false-positive rate for AA in VLBW infants.