Fatimah Harun

Metabolic syndrome among 13 year old adolescents: prevalence and risk factors

BackgroundObesity and metabolic syndrome is prevalent among Malaysian adolescents and has been associated with certain behavioural factors such as duration of sleep, screen time and physical activity. The aim of the study is to report the prevalence of overweight/obesity, metabolic syndrome and its risk factors among adolescents.MethodsA multi-staged cluster sampling method was used to select participants from urban and rural schools in Selangor, Perak and Wilayah Persekutuan Kuala Lumpur. Participants underwent anthropometric measurement and physical examination including blood pressure measurement. Blood samples were taken for fasting glucose and lipids and participants answered a self-administered questionnaire. Overweight and obesity was defined using the extrapolated adult body mass index (BMI) cut-offs of >25 kg/m2 and >30 kg/m2, according to the International Obesity Task Force (IOTF) criteria. Metabolic syndrome was defined based on International Diabetes Federation (IDF) 2007 criteria.ResultsData were collected from 1361 participants. After excluding incomplete data and missing values for the variables, we analysed a sample of 1014 participants. Prevalence of overweight and obesity in this population was 25.4% (N = 258). The prevalence of metabolic syndrome was 2.6% in the population and 10% among the overweight and obese adolescents. Participants who slept between 7 and 9 hours a day has a lower risk of developing metabolic syndrome OR 0.38(0.15-0.94).ConclusionOur results provide the prevalence of metabolic syndrome in Malaysian adolescents. Adequate sleep between 7 and 9 hours per day reduces the risk of developing metabolic syndrome.

Permanent neonatal diabetes due to a novel insulin signal peptide mutation

We report a rare case of permanent neonatal diabetes (PND) due to insulin (INS) gene mutation in a 51‐month‐old girl who presented with hyperglycemia in the neonatal period. Mutational analysis of KCNJ11 and INS was performed and this detected a novel heterozygous c.38T>G (p.Leu13Arg) INS de novo mutation. The non‐conservative change substitutes the highly conserved L13 residue within the hydrophobic core region of the preproinsulin signal peptide. Given the frequent tendency of heterozygous INS mutations to exhibit dominant negative disease pathogenesis, it is likely that the mutant preproinsulin perturbed the non‐mutant counterpart progression and processing within the β‐cells, and this resulted to a permanent form of congenital diabetes.

A Novel, Homozygous c.1502T>G (p.Val501Gly) Mutation in the Thyroid peroxidase Gene in Malaysian Sisters with Congenital Hypothyroidism and Multinodular Goiter.

Congenital hypothyroidism (CH) with multinodular goiter (MNG) is uncommonly seen in children. However, CH associated with goiter is often caused by defective Thyroid peroxidase (TPO) gene. In this study, we screened for mutation(s) in the TPO gene in two siblings with CH and MNG and their healthy family members. The two sisters, born to consanguineous parents, were diagnosed with CH during infancy and received treatment since then. They developed MNG during childhood despite adequate L-thyroxine replacement and negative thyroid antibody screening. PCR-amplification of all exons using flanking primers followed by DNA sequencing revealed that the two sisters were homozygous for a novel c.1502T>G mutation. The mutation is predicted to substitute valine for glycine at a highly conserved amino acid residue 501 (p.Val501Gly). Other healthy family members were either heterozygotes or mutation-free. The mutation was not detected in 50 healthy unrelated individuals. In silico analyses using PolyPhen-2 and SIFT predicted that the p.Val501Gly mutation is functionally “damaging.” Tertiary modeling showed structural alterations in the active site of the mutant TPO. In conclusion, a novel mutation, p.Val501Gly, in the TPO gene was detected expanding the mutation spectrum of TPO associated with CH and MNG.

Characterization of Mutations in the FOXE1 Gene in a Cohort of Unrelated Malaysian Patients with Congenital Hypothyroidism and Thyroid Dysgenesis

The FOXE1 gene was screened for mutations in a cohort of 34 unrelated patients with congenital hypothyroidism, 14 of whom had thyroid dysgenesis and 18 were normal (the thyroid status for 2 patients was unknown). The entire coding region of the FOXE1 gene was PCR-amplified, then analyzed using single-stranded conformational polymorphism, followed by confirmation by direct DNA sequencing. DNA sequencing analysis revealed a heterozygous A>G transition at nucleotide position 394 in one of the patients. The nucleotide transition changed asparagine to aspartate at codon 132 in the highly conserved region of the forkhead DNA binding domain of the FOXE1 gene. This mutation was not detected in a total of 104 normal healthy individuals screened. The binding ability of the mutant FOXE1 protein to the human thyroperoxidase (TPO) promoter was slightly reduced compared with the wild-type FOXE1. The mutation also caused a 5% loss of TPO transcriptional activity.

Prevalence of c.2268dup and detection of two novel alterations, c.670_672del and c.1186C>T, in the TPO gene in a cohort of Malaysian–Chinese with thyroid dyshormonogenesis

Objectives The c.2268dup mutation in the thyroid peroxidase (TPO) gene is the most common TPO alteration reported in Taiwanese patients with thyroid dyshormonogenesis. The ancestors of these patients are believed to originate from the southern province of China. Our previous study showed that this mutation leads to reduced abundance of the TPO protein and loss of TPO enzyme activity in a Malaysian–Chinese family with goitrous hypothyroidism. The aim of our study was to provide further data on the incidence of the c.2268dup mutation in a cohort of Malaysian–Chinese and its possible phenotypic effects. Setting Cohort study. Participants Twelve biologically unrelated Malaysian–Chinese patients with congenital hypothyroidism were recruited in this study. All patients showed high thyrotropin and low free thyroxine levels at the time of diagnosis with proven presence of a thyroid gland. Primary outcome measure Screening of the c.2268dup mutation in the TPO gene in all patients was carried out using a PCR–direct DNA sequencing method. Secondary outcome measure Further screening for mutations in other exonic regions of the TPO gene was carried out if the patient was a carrier of the c.2268dup mutation. Results The c.2268dup mutation was detected in 4 of the 12 patients. Apart from the c.2268dup and a previously documented mutation (c.2647C>T), two novel TPO alterations, c.670_672del and c.1186C>T, were also detected in our patients. In silico analyses predicted that the novel alterations affect the structure/function of the TPO protein. Conclusions The c.2268dup mutation was detected in approximately one-third of the Malaysian–Chinese patients with thyroid dyshormonogenesis. The detection of the novel c.670_672del and c.1186C>T alterations expand the mutation spectrum of TPO associated with thyroid dyshormonogenesis.

Functional analyses of C.2268dup in thyroid peroxidase gene associated with goitrous congenital hypothyroidism.

The c.2268dup mutation in thyroid peroxidase (TPO) gene was reported to be a founder mutation in Taiwanese patients with dyshormonogenetic congenital hypothyroidism (CH). The functional impact of the mutation is not well documented. In this study, homozygous c.2268dup mutation was detected in two Malaysian-Chinese sisters with goitrous CH. Normal and alternatively spliced TPO mRNA transcripts were present in thyroid tissues of the two sisters. The abnormal transcript contained 34 nucleotides originating from intron 12. The c.2268dup is predicted to generate a premature termination codon (PTC) at position 757 (p.Glu757X). Instead of restoring the normal reading frame, the alternatively spliced transcript has led to another stop codon at position 740 (p.Asp739ValfsX740). The two PTCs are located at 116 and 201 nucleotides upstream of the exons 13/14 junction fulfilling the requirement for a nonsense-mediated mRNA decay (NMD). Quantitative RT-PCR revealed an abundance of unidentified transcripts believed to be associated with the NMD. TPO enzyme activity was not detected in both patients, even though a faint TPO band of about 80 kD was present. In conclusion, the c.2268dup mutation leads to the formation of normal and alternatively spliced TPO mRNA transcripts with a consequential loss of TPO enzymatic activity in Malaysian-Chinese patients with goitrous CH.

Variable clinical phenotypes in a family with homozygous c.1159G>A mutation in the thyroid peroxidase gene.

Background: Defects in the thyroid peroxidase (TPO) gene have been associated with goitrous congenital hypothyroidism (CH). Case Report: In this study, we report 3 siblings possessing a homozygous mutation, c.1159G>A, but exhibiting different clinical phenotypes in a Malaysian-Malay family. The index patient was diagnosed with CH during a routine neonatal screening but the other 2 siblings appeared to be asymptomatic until the ages of 19 and 12.5, respectively, when they started to develop goiter. Results and Conclusion: The mutation was predicted to interrupt the correct splicing of pre-mRNA and also lead to structural alterations in the functional sites of the mutant TPO. The current results suggest the association of goiter development with a homozygous c.1159G>A mutation, but the CH in the index patient could be triggered by other genetic and epigenetic factors distinct from the c.1159G>A mutation.

Endogenous Cushing syndrome from an ectopic adrenocorticotropic hormone production as a rare cause of ocular hypertension.

Ocular hypertension caused by endogenous Cushing syndrome from an ectopic adrenocorticotropic hormone-producing tumor is rare. We report an 11-year-old boy who presented with intraocular pressures (IOPs) of 50 mm Hg in both eyes. Surgical resection of the tumor was performed with subsequent normalization of serum cortisol and IOP levels.

Permanent neonatal diabetes due to a heterozygous INS mutation

Permanent Neonatal Diabetes Mellitus (PNDM) is a rare disorder where patient presents with diabetes within the first few months of life without autoantibodies associated with type 1 diabetes. The majority of PNDM cases have INS, ABCC8 or KCNJ11 mutations. We present a PNDM case with INS mutation. The proband is a second child of three siblings without family history of diabetes. She was born at term via emergency lower segment caesarean section with good APGAR score. Her birth weight was 2.0kg (<3rd percentile), length 49cm (50th percentile), and head circumference 34cm (50th percentile). She was discharged well at day 3 of life, but readmitted at day 17 of life with hyperglycaemia, sepsis and severe metabolic acidosis, requiring insulin infusion. Despite clinical improvement and resolving sepsis, she remained hyperglycaemic and hence neonatal diabetes was suspected. Her GAD-65 and ICA-512 antibodies were negative. HbA1c and c-peptide at diagnosis were 7.9% and 38 pmol/L (normal range: 297.9–1324) respectively. She was still hyperglycaemic despite receiving total daily insulin (TDI) of 1.5U/kg/day, but not ketotic. She was discharged after 20 days of hospitalization with insulatard administered three times daily (TDI 1.2U/kg/day). During the first 8 months of diagnosis, her metabolic control was good (HbA1c 6.7 - 7.6%) despite low insulin requirement, as low as 0.4U/kg/day. Her metabolic control deteriorated since then (HbA1c 11.9 - 13.2%), with TDI doses ranging 0.7 - 0.9 U/kg/day. Rapid acting insulin was not used due to episodes of hypoglycaemia and unpredictable eating habit and activity levels during her toddler years. Direct DNA sequencing revealed she is heterozygous for p.A24D INS mutation. This mutation has been reported in the literature and known to disrupt preproinsulin processing. Recent evaluation at 51 month showed, negative anti-islet cell antibodies and c-peptide of <30pmol/L (normal range: 297.9–1324). Currently, her developmental milestone is appropriate for her age. However, her height and weight were both below the 3rd centiles. She was recently started on insulin pump to improve her metabolic control and growth. Written informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.

Vitamin D status of healthy adolescents from two states in Malaysia

Hypovitaminosis D is a widespread disorder across all age groups in developing countries. The prevalence of hypovitaminosis D varies from 30-90% depending on the cut off level used to define hypovitaminosis D. In Malaysia, Khor et. al found 35.3% of 402 primary school children aged 7-12 years to have 25(OH)D level < 37.5nmol/L and 37.1% have the level between 37.5-50nmol/L. If a broader definition of hypovitaminosis < 50nmol/L is used then, the prevalence was as high as 74.6%. The risk factors associated with hypovitaminosis D in developing countries are the same as in western countries. The most consistently reported risk factors are female gender, increased skin pigmentation, seasons/latitudes, obesity, concealing clothing style and vulnerable groups (neonates, preschool, elderly). A total of 469 adolescents (107 PJ, 362 KB) participated in the study. The mean age was 15.6+/-1.4 years. Female gender contributed about 61.0% compared to male gender, 39.1%. As for the race distribution, the proportion of Malay was 79.3%, Chinese 17.7% and Indian 3.0%. Teenagers from KB with family income < RM 1000 was higher (37.8% cf 10.3%; P <0.001). Adolescents from PJ was taller (160.6cm cf 156.3cm; P = 0.02). The mean BMI was 21.0+/-4.4 kgm2. The mean 25(OH)D was19.9+/-8.1, in which PJ had a higher level(21.0 cf 19.6) but the mean differences was not statistically significant. More than half (58%) of adolescents had 25(OH)D < 50nmol/L. The proportion of subjects with 25(OH)D < 50nmol/L was 60.2% in KB and 50.4% in PJ. With regard to the degree of 25(OH)D level, 52% had a level between 25.0-50.0nmol/L, 6% had a level between 12.5-25.0nmol/L. None had a level < 12.5nmol/L. Chinese had the highest mean of 25(OH)D(23.5+/-8.0; P <0.001) compared to the other 2 races. From multiple logistic regression, significant variables were age (0.84;95%CI :0.72,0.98), gender(boy)(0.13;95%CI;0.08,0.19) and race(Chinese)(0.30;05%C1;0.17,0.53). This study highlights a high prevalence of hypovitaminosis D among adolescents especially in younger adolescents, female and darker skin.