Impact of irregular sleep pattern, and sleep quality on glycaemic parameters and endothelial function in adolescents and young adults with type 1 diabetes

This study investigated the impact of comprehensive sleep patterns on glycaemic parameters and endothelial function in adolescents and young adults with type 1 diabetes (T1D). Thirty subjects with type 1 diabetes (aged 13-25) without chronic complications participated. For 1 week, glucose levels were monitored by real-time continuous glucose monitoring (CGM) and sleep was simultaneously assessed by actigraphy. Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Flow-mediated dilatation (FMD) measured endothelial function at the brachial artery. Insulin sensitivity was determined by calculated estimated glucose disposal rate (eGDR). Glycaemic control was assessed using haemoglobin A1C (HbA1C) levels. To address potential confounding by metabolic syndrome on the FMD results, three affected subjects were excluded from FMD correlation analyses. Participants with PSQI scores >5 had a lower %FMD compared with those with scores ≤5 (4.6 ± 3.7% vs. 7.6 ± 3.0%, p = 0.03). Multivariate analysis indicated that lower sleep efficiency and higher sleep duration variability were associated with higher HbA1C levels (β = -0.076, 95%CI [-0.145, -0.008], p = 0.029; β = 0.012, 95%CI [0.001, 0.023], p = 0.033). Irregular sleep timing and lower sleep efficiency were related to decreased insulin sensitivity (sleep midpoint irregularity β = -1.581, 95%CI [-2.661, -0.502], p = 0.004, and sleep efficiency β = 0.147, 95%CI [0.060, 0.235], p = 0.001). No significant associations were found between glycaemic parameters and FMD. Our study demonstrated that sleep irregularity in type 1 diabetes was associated with glycaemic control and insulin resistance, while poor subjective sleep quality was linked to endothelial dysfunction. Promoting healthy sleep habits, including consistent sleep timing could benefit metabolic and cardiovascular health in type 1 diabetes.

Internet analytics of an innovative digital educational resource of type 1 diabetes HelloType1 in local languages for people living with diabetes families and healthcare professionals in Southeast Asia

BACKGROUND

There is minimal data of health outcomes for Type 1 Diabetes (T1D) in Southeast Asia (SEA) where government funding of insulin and blood glucose monitoring either do not exist or is limited. The full impact of Covid-19 pandemic on the national economies of SEA remain unknown. In the midst of the pandemic, in 2021, HelloType1 was developed by Action4Diabetes (A4D), a non-government organisation charity in collaboration with Southeast Asia local healthcare professionals as an innovative digital educational resource platform of T1D in local languages. HelloType1 was launched in Cambodia, Vietnam, Thailand and Malaysia in 2021 to 2022 with Memorandums of Understandings (MOUs) signed between A4D and each country. Internet data analytics were undertaken between the 1st of January 2022 to 31st of December 2022.

AIMS

The aims of this study were to explore the usability and internet data analytics of the HelloType1 online educational platform within each country.

METHODS

The data analytics were extracted Google analytics that tracks data from the website hellotype1.com and Facebook analytics associated with the website.

RESULTS

There was a 147% increase in the number of HelloType1 users between the first 6 months versus the latter 6 months in 2022 and a 15% increase in the number of pages visited were noted. The majority of traffic source were coming from organic searches with a significant increase of 80% growth in 2022.

CONCLUSIONS

The results of the analytics provide important insights on how an innovative diabetes digital educational resource in local languages may be optimally delivered in low-middle income countries with limited resources.

The prevalence of diabetic peripheral neuropathy in youth with diabetes mellitus

BACKGROUNDS

Diabetic neuropathy (DN) is a serious complication in diabetes mellitus. We aimed to determine the prevalence of DN in pediatric-onset diabetes in a tertiary care center and assess the sensitivity and specificity of monofilament test and non-invasive screening to diagnose DN compared with the gold standard nerve conduction studies (NCS).

METHODS

Sixty-five Thai children and adolescents (39 females), diagnosed with diabetes before 15 years old were included. All subjects were screened for DN by foot and neurological examination, light touch sensation by 10 g Semmes-Weinstein monofilaments, and Michigan Neuropathy Screening Instrument. NCS were used as a gold standard for diagnosis of DN.

RESULTS

58 patients had type 1 diabetes (T1D), 5 patients had type 2 diabetes, and 2 patients had other types. Mean age was 17.7±4.6 y (8-33 y). The prevalence of DN in this cohort was 12.3% by NCS. All subjects were asymptomatic. Mean diabetes duration was not different between groups (with DN 8.0±3.0 vs. no DN 8.2±5.0 years). Notably, one patient with T1D developed DN within 3 years after diagnosis. Poor glycemic control was the significant risk factor for DN. HbA1c was higher in DN group (10.6±2.3% vs. 8.5±1.6%, P=0.008). The occurrence of diabetic nephropathy was associated with DN [prevalence rate ratio (95% CI), 4.97 (1.5, 16.46)]. Foot and neurological examination, monofilaments and Michigan Neuropathy Screening Instrument failed to detect DN in all subjects with abnormal NCS.

CONCLUSION

The prevalence of diabetic neuropathy in pediatric-onset diabetes is not uncommon, but mainly subclinical. Poor glycemic control is the main risk factor. Non-invasive screening test for DN had poor diagnostic sensitivity in pediatric population.

Long-read Amplicon Sequencing of the CYP21A2 in 48 Thai Patients With Steroid 21-Hydroxylase Deficiency

CONTEXT

Congenital adrenal hyperplasia is most commonly caused by 21-hydroxylase deficiency (21-OHD), an autosomal recessive disorder resulting from biallelic pathogenic variants (PVs) in CYP21A2. With a highly homologous pseudogene and various types of single nucleotide and complex structural variants, identification of PVs in CYP21A2 has been challenging.

OBJECTIVE

To leverage long-read next-generation sequencing combined with locus-specific polymerase chain reaction (PCR) to detect PVs in CYP21A2 and to determine its diagnostic yield in patients with 21-OHD.

METHODS

Forty-eight Thai patients with 21-OHD comprising 38 sporadic cases and 5 pairs of siblings were enrolled. Two previously described locus-specific PCR methods were performed. Amplicons were subject to long-read sequencing.

RESULTS

Ninety-six PVs in CYP21A2 in the 48 patients were successfully identified. The combined techniques were able to detect 26 structural chimeric variants (27%; 26/96) in 22 patients with 18 having monoallelic and 4 having biallelic chimeras. The remaining PVs were pseudogene-derived mutations (63%; 60/96), entire gene deletions (2%; 2/96), missense variants (3%; 3/96), a splice-site variant (2%; 2/96), frameshift variants (2%; 2/96), and a nonsense variant (1%; 1/96). Notably, a splice-site variant, IVS7 + 1G > T, which was identified in a pair of siblings, has not previously been reported.

CONCLUSIONS

Our approach exploiting locus-specific PCR and long-read DNA sequencing has a 100% diagnostic yield for our cohort of 48 patients with 21-OHD.

Young-onset diabetes patients in Thailand: Data from Thai Type 1 Diabetes and Diabetes diagnosed Age before 30 years Registry, Care and Network (T1DDAR CN)

AIMS/INTRODUCTION

There is a lack of current information regarding young-onset diabetes in Thailand. Thus, the objectives of this study were to describe the types of diabetes, the clinical characteristics, the treatment regimens and achievement of glycemic control in Thai patients with young-onset diabetes.

MATERIALS AND METHODS

Data of 2,844 patients with diabetes onset before 30 years-of-age were retrospectively reviewed from a diabetes registry comprising 31 hospitals in Thailand. Gestational diabetes was excluded.

RESULTS

Based on clinical criteria, type 1 diabetes was identified in 62.6% of patients, type 2 diabetes in 30.7%, neonatal diabetes in 0.8%, other monogenic diabetes in 1.7%, secondary diabetes in 3.0%, genetic syndromes associated with diabetes in 0.9% and other types of diabetes in 0.4%. Type 1 diabetes accounted for 72.3% of patients with age of onset <20 years. The proportion of type 2 diabetes was 61.0% of patients with age of onset from 20 to <30 years. Intensive insulin treatment was prescribed to 55.2% of type 1 diabetes patients. Oral antidiabetic agent alone was used in 50.8% of type 2 diabetes patients, whereas 44.1% received insulin treatment. Most monogenic diabetes, secondary diabetes and genetic syndromes associated with diabetes required insulin treatment. Achievement of glycemic control was identified in 12.4% of type 1 diabetes patients, 30% of type 2 diabetes patients, 36.4% of neonatal diabetes patients, 28.3% of other monogenic diabetes patients, 45.6% of secondary diabetes patients and 28% of genetic syndromes associated with diabetes patients.

CONCLUSION

In this registry, type 1 diabetes remains the most common type and the prevalence of type 2 diabetes increases with age. The majority of patients did not achieve the glycemic target, especially type 1 diabetes patients.

Implementation of Diabetes Care and Educational Program via Telemedicine in Patients with COVID-19 in Home Isolation in Thailand: A Real-World Experience

Background

The coronavirus disease (COVID‐19) outbreak in Bangkok led to a shortage of hospital capacity, and a home isolation system was set up. We described the process of diabetes self‐management education and support (DSMES) and glycemic management via telemedicine, along with outcomes in home‐isolated patients with COVID‐19 infection.

Methods

A retrospective chart review of glucose values, insulin and corticosteroids use, and outcomes was performed.

Results

A volunteer group of 21 endocrinologists and 21 diabetes educators/nurses formed the consultation team. Patients with diabetes or at high‐risk of diabetes and receiving corticosteroids were referred by primary volunteer physicians. Glucometers and related supplies, and insulin were donated, and delivered via same‐day delivery services. A chat group of an individual patient/their caregiver, diabetes educator, endocrinologist, and primary physician was formed (majority via LINE^® platform) to assess the patient's clinical status and need. Real‐time virtual DSMES sessions were performed and treatments were adjusted via smartphone application or telephone. There were 119 patients (1,398 service days), mean (SD) age 62.0 (13.6) years, 85.7% had a history of type 2 diabetes, and 84.0% received corticosteroids. Insulin was used in 88 patients; 69 of whom were insulin‐naïve. During the first 10 days, there were 2,454 glucose values. The mean glucose level on day 1 was 280.6 (122.3) mg/dL, and declined to 167.7 (43.4) mg/dL on day 10. Hypoglycemia occurred in 1.4% of the values. A majority of patients (79.5%) recovered at home.

Conclusion

Diabetes care and DSMES delivered via telemedicine to patients on home isolation during COVID‐19 pandemic was safe and effective.

Outcomes of a multidisciplinary transition clinic for youth with type 1 diabetes

BACKGROUND

Emerging adults with type 1 diabetes (T1D) have several challenges regarding diabetes management and care transition from pediatric to adult services. In this study we aimed to assess the effectiveness of the newly established transition clinic for emerging adults with T1D.

METHODS

We conducted an observational study of emerging adults with T1D treated in a transition clinic jointly operated by a pediatric and adult multidisciplinary care team during 2019-2021. A retrospective chart review of hemoglobin A1c (HbA1c), frequency of clinic attendance, acute diabetes-related complications, assessment of gaps in knowledge and behavior, and psychosocial outcomes was analyzed.

RESULTS

A total of 21 patients with T1D were included. Median age at the transfer to the transition clinic was 24 years (range 21-34). Fifteen patients (71%) were successfully transferred to adult services; mean duration of follow-up at the transition clinic was 9.2 months (SD 3.9). None of the patients was lost to follow-up or experienced serious diabetes related complications. Mean (95% confidence interval) HbA1c levels decreased from 8.97% (7.87-10.07) at baseline to 8.25% (7.45-9.05) at the most recent visit (p = 0.01). A proportion of patients achieving the glycemic target (HbA1c < 7.5%) was increased from 24% at the first visit to 38% at the most recent visits. Patients' HbA1c levels at the adult clinic continued a favorable trend. Seven patients (33%) were identified as having symptoms of depression. Knowledge and behavioral gaps were identified and counselled by clinical care team.

CONCLUSION

The multidisciplinary transition clinic has shown to be beneficial in terms of improving glycemic control, maintaining continuity of care and clinic attendance.

The Prevalence of Nonalcoholic Fatty Liver Disease and Its Risk Factors in Children and Young Adults with Type 1 Diabetes Mellitus

OBJECTIVES

To determine the prevalence of nonalcoholic fatty liver disease (NAFLD) and its associated risk factors in children and young adults with type 1 diabetes (T1D).

STUDY DESIGN

A cross-sectional study was conducted at a tertiary care center in children and young adults with T1D. Liver fat quantification and hepatic fibrosis were assessed by magnetic resonance imaging proton density fat fraction and magnetic resonance elastography (MRE). Logistic regression analysis was performed to examine the associated risk factors for NAFLD.

RESULTS

Fifty patients with T1D (28 females, 13 with overweight/obesity) were included. The median age and duration of T1D were 16.9 years (IQR, 13.6-20 years) and 6.5 years (IQR, 4-11 years), respectively. The prevalence of NAFLD was 10%. Four out of 5 patients with NAFLD were overweight/obese, and 2 had an and elevated alanine aminotransferase (ALT) level. None had liver fibrosis (defined as MRE >2.9 kPa). Compared with patients without NAFLD, patients with NAFLD had significantly higher body mass index standard deviation score (BMI-SDS) (median, 0.94 [IQR, 1.30-2.62] vs 0.13 [IQR, -0.69 to 0.84]; P = .01), ALT (median, 17 IU/L [IQR, 16-52 IU/L] vs 12 IU/L [IQR, 10-14 IU/L]; P = .02), and lower high-density lipoprotein cholesterol (median, 49 mg/dL [IQR, 41-51 mg/dL] vs 57 mg/dL [IQR, 52-69 mg/dL]; P = .039). Multivariate logistic regression analysis identified high BMI-SDS as the sole independent risk factor associated with NAFLD (OR, 5.79; 95% CI, 1.04-32.18).

CONCLUSION

The prevalence of NAFLD in children and young adults with T1D was comparable to that in the general population. Our study suggests that routine screening for NAFLD in patients with T1D might not be necessary but should be performed in those patients with T1D who are overweight/obese.

Type 1 diabetes management and outcomes: A multicenter study in Thailand

Aims/Introduction

The Thai Type 1 Diabetes and Diabetes Diagnosed Before Age 30 Years Registry, Care and Network was established in 2014 and involved 31 hospitals. The objective of the registry was to evaluate glycemic control and complications of patients with type 1 diabetes.

Materials and Methods

Patients’ demographics, clinical data, frequencies of daily self‐monitoring of blood glucose (SMBG), glycemic control and complications were collected.

Results

Among the 1,907 type 1 diabetes patients, the mean age was 21.2 ± 11.3 years. The mean glycated hemoglobin level was 9.35 ± 2.41%, with significant variations among age groups (P < 0.001). Conventional insulin treatment and intensive insulin treatment were used in 43 and 57% of patients, respectively. Mean glycated hemoglobin levels were significantly higher in patients treated with conventional insulin treatment compared to those treated with intensive insulin treatment (9.63 ± 2.34 vs 9.17 ± 2.46%, P = 0.002). Compared to the conventional insulin treatment group, significantly more patients in the intensive insulin treatment group achieved good glycemic control (P < 0.001), and fewer had diabetic retinopathy (P = 0.031). The prevalence of microvascular complications increased significantly with age (P < 0.001). Multivariate analysis showed good glycemic control to be associated with age 25 to <45 years, intensive insulin treatment with SMBG three or more times daily and diabetes duration of 1 to <5 years.

Conclusions

Most Thai type 1 diabetes patients were not meeting the recommended glycemic target. As a result of this study, the national program to improve the quality of diabetes treatment and education has been implemented, and the results are ongoing.

Metabolic features and changes in glucose-induced serum glucagon-like peptide-1 levels in children with hypothalamic obesity

Background Hypothalamic damage may alter glucagon-like peptide-1 (GLP-1) secretion and be involved in the pathogenesis of obesity. We aim to evaluate the metabolic features and the dynamic changes of GLP-1 levels during an oral glucose tolerance test (OGTT) in children with hypothalamic obesity (HO) compared with simple obesity controls. Methods Subjects included eight patients (six females, aged 9-16 years) with hypothalamo-pituitary tumors who later developed obesity and eight controls with simple obesity matched for age, body mass index (BMI), gender and puberty. We assessed the metabolic syndrome features, fat mass, severity of hyperphagia using a standardized questionnaire, and measured glucose, insulin and GLP-1 levels during a standard 75 g OGTT. Results Age, gender distribution, pubertal status and BMI-Z scores were not significantly different. Subjects with HO had higher fasting triglycerides (TG) than controls (128 vs. 94 mg/dL; p=0.05). Four HO subjects and three controls met the criteria for the metabolic syndrome. Fasting and 120 min post-glucose load GLP-1 levels were significantly higher in HO patients than in controls (21.9 vs. 19.7 pg/mL; p=0.025, 22.1 vs. 17.7 pg/mL; p=0.012). Patients with HO had significantly higher hyperphagia scores than in simple obese controls (13 vs. 2.5; p=0.012). Conclusions Patients with HO appear to have more metabolic complications and hyperphagia than controls with simple obesity. Impaired satiety may play an important role in HO. Fasting and glucose-induced serum GLP-1 concentrations seem to be altered in HO patients and could be a part of the pathogenesis of HO.

Frequency of HLA-DQB1*0201/02 and DQB1*0302 alleles and tissue transglutaminase antibody seropositivity in children with type 1 diabetes mellitus

BACKGROUND

Patients with type 1 diabetes mellitus (T1DM) have an increased risk of celiac disease (CD). Both diseases have a common genetic susceptibility locus in the human leukocyte antigen (HLA) class II alleles. Testing for tissue transglutaminase antibodies (anti-tTG) is highly accurate for a CD diagnosis.

OBJECTIVE

To determine the frequency of HLA-DQB1*0201/02 and DQB1*0302 alleles and anti-tTG seropositivity in children with T1DM.

METHOD

Forty-six children with T1DM (male:female=24:22; mean age 12±3.7 years) without significant digestive symptoms were enrolled. The mean duration of diabetes was 5±3.5 years. Serum anti-tTG IgA and IgG as well as HLA-DQ2 (DQB1*0201/02) and -DQ8 (DQB1*0302) alleles were analyzed. The allele frequencies were compared with those in controls, which included 124 normal Thai individuals, as reported in our previous study.

RESULTS

All subjects were negative for anti-tTG IgG. Only one patient (2.2%) was positive for anti-tTG IgA (38.5 U/mL; cut-off 15 U/mL). Although this patient was also heterozygous for HLA-DQ2 and was asymptomatic for CD, he declined endoscopic confirmation. Twenty-nine of 46 patients carried HLA-DQ2 and/or -DQ8 heterodimers. HLA-DQB1*0201/02 and HLA-DQB1*0302 allele frequencies were significantly higher (27% and 14%) in T1DM patients compared with normal controls (13.3% and 7.3%; P<0.001 and P=0.002, respectively).

CONCLUSIONS

A significantly greater frequency of DQB1*0201/02 and DQB1*0302 alleles were present in children with T1DM compared with the control group. This indicates a potentially important role of these alleles in the development of T1DM. The prevalence of CD screening by serologic testing is negligible in Thai children with T1DM.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Identification and Functional Analysis of Six DAX1 Mutations in Patients With X-Linked Adrenal Hypoplasia Congenita

Context

DAX1 (NR0B1) mutations cause X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH) in affected male patients. Affected individuals typically present with early-onset adrenal insufficiency and develop HH during puberty. Rare cases can present with late-onset adrenal insufficiency or other unusual phenotypes.

Objectives

We sought to identify and functionally characterize DAX1 mutations in seven Thai male subjects in six families with X-linked AHC.

Patients and Methods

Six patients had classic phenotypes with early-onset adrenal failure. One patient presented with late-onset Addison disease at 17 years. In the early-onset group, one patient had GnRH-independent sexual precocity at 3 years of age, and another patient had growth hormone deficiency. The DAX1 gene was sequenced from all patients, and the transcriptional activities of the identified mutations were assessed in vitro using luciferase assays.

Results

DAX1 mutations were identified in all patients, including three novel mutations [c.363delG (p.Gly122Valfs*142), c.1062delC (p.Ala355Profs*17), and c.1156C>T (p.Leu386Phe)] and three known mutations [c.1148_1149delGG (p.Gly383Aspfs*5), c.501_502insG (p.Ala170Argfs*15), and c.805_807delGTC (p.Val269del)]. Functional studies showed that the DAX1 mutants had lower levels of repressor activity on the StAR gene promoter compared with the wild-type DAX-1 protein.

Conclusions

This study describes unusual phenotypes and three novel mutations, extending the phenotypic and mutational spectra of DAX1 mutations.

Prevalence of islet autoantibodies in Thai juvenile-onset type 1 diabetes

BACKGROUND

Type 1 diabetes mellitus (T1DM) is caused by autoimmune destruction of islet β-cells of the pancreas. There are overlapping phenotypes in a significant proportion of youth with type 1 and 2 diabetes. Thus, positive pancreatic autoantibodies are helpful to diagnose T1DM. Zinc transporter 8 antibody (ZnT8A) is a recently identified autoantibody in T1DM and no data on ZnT8A in the Thai population have been reported. The aim of this study was therefore to estimate the prevalence of ZnT8A in Thai juvenile-onset T1DM and to evaluate its diagnostic value relative to glutamic acid decarboxylase and insulinoma-2 antigen antibodies (GADA and IA2A).

METHODS

In this cross-sectional study, patients with T1DM diagnosed before age 15 years, and disease duration <10 years were enrolled. Serum ZnT8A, GADA, and IA2A were measured using commercial enzyme-linked immunosorbent assay kits.

RESULTS

The subjects consisted of 81 youths (30 boys, 51 girls) aged 12.3 ± 4.5 years with T1DM. The median diabetes duration was 3 years (range, 0-10 years). The prevalence of ZnT8A, GADA, and IA2A was 54.3%, 75.3%, and 45.7%, respectively. ZnT8A were detected in 16% of T1DM patients negative for both GADA and IA2A. A combination of ZnT8A, GADA and IA2A could detect 80.2% of patients with T1DM. Combined use of ZnT8A and GADA identified 100% of antibody-positive patients.

CONCLUSION

The prevalence of ZnT8A in Thai juvenile-onset T1DM appears to be higher than in previous studies from Asia. ZnT8A could replace IA2A as an autoimmunity marker in Thai pediatric T1DM patients, with better diagnostic performance.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Factors associated with glycemic control in children and adolescents with type 1 diabetes mellitus at a tertiary-care center in Thailand: a retrospective observational study

Background

Children and adolescents with type 1 diabetes mellitus (T1D), even those with intensive insulin treatment regimens, often have higher glycated hemoglobin (HbA1c) levels than adults.

Objective

To delineate the medical and psychosocial factors associated with glycemic control in an unselected pediatric population with T1D.

Methods

We included a cross-section of 58 adolescents (28 boys and 30 girls) aged 13.6 ± 4.0 years with T1D ≥1 year attending a well-established pediatric diabetes clinic in Thailand. Median diabetes duration was 4.1 years (range 1–18 years). Participants were divided into 2 subgroups according to their average HbA1c level over the past year. Those with good control (HbA1c <8%) (n = 13) were compared with those with poor control (HbA1c ≥8%) (n = 45). Data collected from self-report standardized questionnaires and medical records were used to compare variables between groups.

Results

Adolescents with good control used significantly less daily insulin and had higher family income, higher scores for family support, and quality of life (QoL) than those in the group with poor control (P < 0.05). Age, sex, puberty, duration of diabetes, insulin regimen, frequency of blood glucose monitoring, and self-report adherence did not differ between groups. By univariate logistic regression, the only factor associated significantly with poor glycemic control was a QoL score <25.

Conclusion

Adolescents with T1D may be at a higher risk of poor glycemic control if they have poor QoL, impaired family functioning, poor coping skills, and lower socioeconomic status, suggesting that psychosocial interventions could potentially improve glycemic control in this population.

Cardio-metabolic risk factors in youth with classical 21-hydroxylase deficiency

Patients with congenital adrenal hyperplasia (CAH) appear to have adverse cardiovascular risk profile and other long-term health problems in adult life, but there are limited data in young CAH patients. We aim to evaluate the cardio-metabolic risk factors in adolescents and young adults with classical 21-hydroxylase deficiency (21-OHD). We performed a cross-sectional study of 21 patients (17 females) with classic CAH detected clinically and not through newborn screening, aged 15.2 ± 5.8 years, and 21 healthy matched controls. Anthropometric, biochemical, inflammatory markers, and body composition using dual-energy X-ray absorptiometry were measured. Obesity was observed in 33% of the CAH patients. The waist/hip ratio and waist/height ratio were significantly higher in CAH patients. Five out of 21 patients (24%) had elevated blood pressure. Silent diabetes was diagnosed in one patient (4.8%), but none in the control group. Serum leptin and interleukin-6 levels were not different between groups, but hs-CRP levels tended to be higher in CAH patients. Other metabolic profiles and body composition were similar in CAH and controls.

CONCLUSION

Adolescents and young adults with CAH appear to have an increased risk of obesity and cardio-metabolic risk factors. Close monitoring, early identification, and secondary prevention should be implemented during pediatric care to improve the long-term health outcomes in CAH patients. What is Known: • Lifelong glucocorticoid (GC) replacement is the main treatment modality in patients with congenital adrenal hyperplasia which predispose to an adverse metabolic profile. • Adult CAH patients have adverse cardiovascular risk profile and other long-term health problems. What is New: • Adolescents and young adults with CAH appear to have an increased risk of obesity and cardio-metabolic risk factors.

Original article. Trends and characteristics of childhood diabetes in a tertiary care center in Thailand

Background: Reports on characteristics of pediatric diabetes in children from Southeast Asian countries are limited.

Objectives: To describe the clinical characteristics, prevalence, glycemic control, and current treatment regimens of diabetes in Thai children.

Materials and Methods: Data from 132 patients seen at our pediatric diabetes clinic at Chulalongkorn University during 2001−2013 were retrospectively reviewed.

Results: We found an increasing number of patients newly-diagnosed with type 1- (T1DM) or type 2- diabetes mellitus (T2DM). The overall proportion of T1DM was 69.7%, T2DM 23.4%, and other types 6.9%. Children with T1DM were younger at diagnosis, had higher initial glucose and glycated hemoglobin A1c (HbA1c), a lower body mass index z-score, lower C-peptide and insulin levels, and were more likely to have classic diabetes symptoms and ketoacidosis, compared with children with T2DM. Mixed diabetes phenotypes were found in about 12%−14% of these children. Glutamic acid decarboxylase and islet antigen-2 autoantibodies were found in 70% and 54% of T1DM patients, respectively, and not in T2DM patients. HbA1c in T1DM was 9.6 ± 2.2% total hemoglobin, and in T2DM was 7.9 ± 2.6%. There were no differences in HbA1c levels between different insulin regimens in the T1DM group.

Conclusion: The number of children with T1DM or T2DM has been increasing and there are overlapping phenotypes in a significant proportion of these children. Correct diagnosis requires clinical evaluation and monitoring of the clinical course. Further research is needed to determine the risk factors for the poor glycemic control found in children with T1DM.

Testicular function in patients with regular blood transfusion for thalassemia major

Background

Regular blood transfusion and iron chelation therapy have improved the quality of life of patients with thalassemia and increased their longevity, but transfusion also increases the frequency of endocrine complications, possibly because of iron deposition in the pituitary gland or the gonads, or both.

Objective

To evaluate testicular function in patients with thalassemia major by basal hormonal study, and identify risk factors for dysfunction.

Methods

We performed a cross-sectional study of 28 patients with thalassemia major aged 11.7 ± 1.8 (8–14.9) years (15 in prepuberty, 13 in puberty with no delayed puberty) who had regular blood transfusions. A normal control group comprised 64 boys who were matched for age and Tanner genital stage.

Results

The mean level of serum ferritin in the previous year was 1,575 ± 642 ng/mL, and the onset of blood transfusion was at 3.8 ± 2.3 years and iron chelation therapy was 6.6 ± 2.8 years. The trend for anti-Müllerian hormone levels in patients and controls was similar with age, and although higher in the patients, particularly at Tanner stage II, was not significantly different. Testosterone levels were lower in the patients compared with controls; particularly at Tanner stages IV–V (290.88 vs. 537.4 ng/dL, P < 0.05). Serum follicle-stimulating hormone and luteinizing hormone levels were not significantly different between the groups at any Tanner stage.

Conclusion

Patients who received regular blood transfusions had normal Sertoli cell function. Leydig cell dysfunction may occur, even though the patients had a normal pubertal onset.

Novel mutations of the SRD5A2 and AR genes in Thai patients with 46, XY disorders of sex development

BACKGROUND

Abnormalities of dihydrotestosterone conversion [5α-reductase deficiency: online Mendelian inheritance in man (OMIM) 607306] or actions of androgens [partial androgen insensitivity syndrome (PAIS): OMIM 312300] during the 8th-12th weeks of gestation cause varying degrees of undervirilized external genitalia in 46, XY disorders of sex development (DSD) with increased testosterone production. The objective of the study was to determine clinical and genetic characteristics of Thai patients with 46, XY DSD.

METHODS

A cross-sectional study was conducted in 46, XY DSD with increased testosterone production (n=43) evaluated by a human chorionic gonadotropin (hCG) stimulation test or clinical features consistent with 5α-reductase deficiency or PAIS. PCR sequencing of the entire coding regions of the SRD5A2 and AR genes was performed. Molecular modeling analysis of the androgen receptor-ligand-binding domain (AR-LBD) of a novel mutation was constructed.

RESULTS

Mutations were found in seven patients (16.3%): five (11.6%) and two (4.7%) patients had mutations in SRD5A2 and AR, respectively. Two novel mutations, SRD5A2 c.383A>G (p.Y128C) and AR c.2176C>T (p.R726C), were identified. Dimensional structural analysis of the novel mutated AR (p.R726C) revealed that it affected the co-activator binding [binding function-3 (BF-3)], not the testosterone binding site. Short phallus length was associated with 5α-reductase deficiency.

CONCLUSIONS

Around 16.3% of our patients with 46, XY DSD had 5α-reductase deficiency or PAIS. Two novel mutations of SRD5A2 and AR were identified. The novel mutated AR (p.R726C) might affect the co-activator binding (BF-3), not the testosterone binding site.

A girl with permanent neonatal diabetes due to KCNJ11 mutation presented with Mauriac syndrome after improper adjustment in sulfonylurea dosage over 6 years

Mauriac syndrome is characterized by growth impairment, Cushingoid features, and hepatomegaly in patients with poorly controlled type 1 diabetes mellitus (T1DM). We report a novel presentation of Mauriac syndrome in a 9-year-old girl who was diagnosed with neonatal diabetes at 3 months of age due to the p.R201C mutation in KCNJ11. She was initially treated successfully with glipizide at a dose of 0.85 mg/kg/day but after being lost to follow-up and having improper adjustment in dose over many years, the recent dose of 0.6 mg/kg/day appears to have been insufficient for glycemic control but enough to maintain a low level of C-peptide and prevent diabetic ketoacidosis. With proper insulin administration, all presenting clinical characteristics were resolved within 1 month. A review of the literature relating to clinical manifestations of Mauriac syndrome in children with diabetes was performed and included in this report for comparison with our patient. While Mauriac syndrome has been traditionally associated with T1DM, the presence of Mauriac syndrome should not be excluded in other types of diabetes mellitus.

Splicing analysis of CYP11B1 mutation in a family affected with 11β-hydroxylase deficiency: case report

BACKGROUND

Congenital adrenal hyperplasia (CAH) due to steroid 11β-hydroxylase deficiency (11β-OHD) is a rare form of CAH associated with low renin hypertension, hypokalemia, hyperandrogenemia and ambiguous genitalia in affected females. Herein we describe the clinical, hormonal and molecular characteristics of two Uzbekistan siblings with 11β-OHD and analyze the effects of a splicing mutation.

CASE PRESENTATION

A 46,XX girl presented with genital ambiguity and low renin hypertension; her 46,XY brother presented with precocious puberty. Hormonal studies suggested 11β-OHD. Mutation analysis was performed by PCR followed by Sanger sequencing of the entire coding regions and their flanking introns of the CYP11B1 gene. Mutation analysis showed that both patients were compound heterozygous for IVS7 + 1G > A, and c.421C > T. Although the identified mutations have been previously described, this is, to our knowledge, the first report of these mutations in compound heterozygotes. A minigene assay was used to determine the effects of the splicing mutation. The constructs containing either the wild-type or the splice-site mutant CYP11B1 genomic DNA of exons-introns 6-9 were transfected into COS-7 cells; subsequently, RNA splicing was assessed by reversed transcribed-PCR of CYP11B1 complementary DNA. The minigene assay revealed that the IVS7 + 1G > A mutation resulted in two shorter incorrectly spliced products; one skipping the exon 7 and the other skipping the exons 7-8. The c.421C > T mutation leads to the introduction of a premature stop codon at residue 141 (p.R141X). These mutations are expected to code non-functional proteins.

CONCLUSION

Compound heterozygous mutations (IVS7 + 1G > A and p.R141X) in the CYP11B1 gene were found to cause 11β-OHD. The IVS7 + 1G > A mutation causes aberrant splicing of CYP11B1 leading to exon skipping. This finding could facilitate the future novel therapies targeted on splicing modulation to treat human disease.

Insulin dynamics and biochemical markers for predicting impaired glucose tolerance in obese Thai youth

BACKGROUND

Subjects with impaired glucose tolerance (IGT) are at risk for type 2 diabetes mellitus (T2DM) and cardiovascular disease. The predictors of IGT in obese youth are not well described.

METHODS

We studied 115 obese Thai children who underwent an oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were calculated for assessment of β-cell function. Hemoglobin A1c (HbA1c), lipid profile, and clinical parameters were also used to determine predictors of IGT.

RESULTS

We found that three patients had T2DM and 30 subjects had IGT. IGT patients had significantly higher fasting glucose (FG), 1-h postload glucose, 2-h postload insulin, and lower whole-body insulin sensitivity indices than in normal glucose tolerance subjects whereas other indices were comparable. By ROC curve analyses, 1-h postload glucose was the best predictor of IGT, but FG or HbA1c represented a poor diagnostic tool for prediabetes screening. Subjects with 1-h OGTT glucose > 155 mg/dL had significantly lower high-density lipoprotein levels, lower insulin sensitivity, and more insulin resistance than those with 1-h postload glucose of ≤ 155 mg/dL.

CONCLUSIONS

Abnormal glucose tolerance is highly prevalent in obese Thai youth. Several fasting indices and HbA1c fail to predict IGT. An 1-h OGTT glucose of > 155 mg/dL appears to be more associated with adverse insulin dynamics and metabolic profile than 2-h postload glucose.

Clinical and molecular review of atypical congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is one of the most common inherited metabolic disorders. It comprises a group of autosomal recessive disorders caused by the mutations in the genes encoding for steroidogenic enzymes that involved cortisol synthesis. More than 90% of cases are caused by a defect in the enzyme 21-hydroxylase. Four other enzyme deficiencies (cholesterol side-chain cleavage, 17α-hydroxylase [P450c17], 11β-hydroxylase [P450c11β], 3β-hydroxysteroid dehydrogenase) in the steroid biosynthesis pathway, along with one cholesterol transport protein defect (steroidogenic acute regulatory protein), and one electrontransfer protein (P450 oxidoreductase) account for the remaining cases. The clinical symptoms of the different forms of CAH result from the particular hormones that are deficient and those that are produced in excess. A characteristic feature of CAH is genital ambiguity or disordered sex development, and most variants are associated with glucocorticoid deficiency. However, in the rare forms of CAH other than 21-hydroxylase deficiency so-called "atypical CAH", the clinical and hormonal phenotypes can be more complicated, and are not well recognized. This review will focus on the atypical forms of CAH, including the genetic analyses, and phenotypic correlates.

Germline and somatic DICER1 mutations in a pituitary blastoma causing infantile-onset Cushing's disease

CONTEXT

Pituitary blastoma causing Cushing's syndrome in infancy is very rare, and its molecular pathomechanism is not well understood.

OBJECTIVE

Our objective was to identify genetic changes of a pituitary blastoma causing infantile-onset Cushing's syndrome in a Thai girl without a family history of cancers.

METHODS

Genomic DNA from both leukocytes and tumor tissues was used for whole-exome sequencing (WES) and Sanger sequencing of DICER1. The cDNA reverse-transcribed from RNA extracted from both leukocytes and tumor tissues was used for Sanger sequencing, quantitative real-time PCR (qRT-PCR), and pyrosequencing of DICER1.

RESULTS

WES of leukocytes identified a novel heterozygous c.3046delA (p.S1016VfsX1065) mutation in the DICER1 gene. WES of the tumor tissues detected the same frameshift germline mutation and another novel somatic missense c.5438A→T (p.E1813V) mutation. Both mutations were validated by Sanger sequencing. Quantitative real-time PCR revealed that the DICER1 mRNA levels of the tumor tissues were 54% compared with those of her leukocytes. Pyrosequencing showed that the deletion allele constituted 12% and 0% of the DICER1 cDNA of the proband's leukocytes and tumor tissues, respectively.

CONCLUSION

Our study extends the phenotypic and mutational spectrum of DICER1 mutations to include infantile-onset Cushing's disease and 2 novel mutations. Loss of function of both DICER1 alleles appears to be crucial to initiate tumor development.

Novel AQP2 mutation causing congenital nephrogenic diabetes insipidus: challenges in management during infancy

Congenital nephrogenic diabetes insipidus (NDI) is a rare inherited disorder, mostly caused by AVPR2 mutations. Less than 10% of cases are due to mutations in the aquaporin-2 (AQP2) gene. Diagnosis and management of this condition remain challenging especially during infancy. Here, we report two unrelated patients, a 6-month-old Thai boy and a 5-year-old Emirati girl, with a history of failure to thrive, chronic fever, polydipsia, and polyuria presented in early infancy. The results of water deprivation test were compatible with a diagnosis of NDI. The entire coding regions of the AVPR2 and AQP2 gene were amplified by polymerase chain reaction and sequenced. Patient 1 was homozygous for a novel missense AQP2 mutation p.G96E, inherited from both parents. Patient 2 harbored a previously described homozygous p.T126M mutation in the AQP2 gene. Both patients were treated with a combination of thiazide diuretics and amiloride. Patient 1 developed paradoxical hyponatremia and severe dehydration 2 weeks after medical treatment began. In conclusion, we report a novel mutation of the AQP2 gene and highlight an important role of genetic testing for definite diagnosis. Vigilant monitoring of the fluid status and electrolytes after beginning the therapy is mandatory in infants with NDI.

A novel homozygous Q334X mutation in the HSD3B2 gene causing classic 3β-hydroxysteroid dehydrogenase deficiency: an unexpected diagnosis after a positive newborn screen for 21-hydroxylase deficiency

BACKGROUND

3β-hydroxysteroid dehydrogenase (3βHSD) type 2 (encoded by HSD3B2) is expressed in the adrenals and gonads. HSD3B2 mutations cause the rare form of congenital adrenal hyperplasia '3βHSD deficiency'. In its classic form, affected individuals have salt wasting early in infancy and may have ambiguous genitalia in both sexes. The presence of peripheral type 1 3βHSD often complicates the hormonal diagnosis of this disorder, in that very high 17α-hydroxypregnenolone levels can be converted extra-adrenally to 17α-hydroxyprogesterone (17OHP).

PATIENT AND METHODS

A 46,XX female newborn with no signs of virilization was referred for evaluation of positive 17OHP newborn screening, and developed a salt-wasting crisis at 13 days of age. The confirmatory test revealing highly elevated 17OHP suggested a 21-hydroxylase deficiency, but sequencing of the CYP21A2 gene was not consistent. Further family history suggested a 3βHSD deficiency. The HSD3B2 gene was then sequenced.

RESULTS

The patient was homozygous for the novel nonsense mutation Q334X in the HSD3B2 gene, inherited from both parents.

CONCLUSIONS

We report a novel mutation of the HSD3B2 gene, Q334X, responsible for a classic 3βHSD deficiency. The clinical and hormonal phenotypes can be complicated in this disorder, and this supports the benefits of 17OHP newborn screening to detect various forms of congenital adrenal hyperplasia.

Preliminary study of renal hemodynamic alteration in early childhood diabetes mellitus

Renal hemodynamic study was performed in eight patients associated with type 1, early childhood diabetes mellitus (DM) and seven patients associated with type 2, early childhood DM. The results in both types of DM revealed a significant reduction in peritubular capillary flow and a high value of glomerular filtration rate (GFR) in the presence of reduced renal perfusion characteristic of glomerular hyperfiltration. These findings imply that renal ischemia has already developed in both types of early stage childhood DM and GFR is overestimated in DM, which may mislead to improper interpretation of renal function.

Novel CYP11B2 mutation causing aldosterone synthase (P450c11AS) deficiency

Aldosterone synthase (P450c11AS) deficiency is a rare autosomal recessive disorder, presenting with severe salt-losing in early infancy. It is caused by inactivating mutations of the CYP11B2 gene. Here, we describe three unrelated Asian patients who have clinical and hormonal features compatible with aldosterone synthase deficiency and identify their CYP11B2 mutations. Patient 1 was a Thai female infant. Patient 2 was an Indian boy, and patient 3 was a Thai male infant. All subjects presented at the age of 1-2 months with diarrhea, failure to thrive, and severe dehydration. Their plasma electrolytes showed hyponatremia, hyperkalemia, and acidosis. All patients had normal cortisol response and had elevated plasma renin activity with low aldosterone levels. The entire coding regions of the CYP11B2 gene were amplified by polymerase chain reaction and sequenced. Patient 1 was homozygous for a previously described mutation, p.T318M. Patient 2 was homozygous for a novel c.666delC mutation inherited from both parents resulting in p.223F>Sfsx295. No CYP11B2 mutation was detected in patient 3.

CONCLUSIONS

We report the first CYP11B2 defects in Southeast Asian families responsible for aldosterone synthase deficiency and identified a novel CYP11B2 mutation. However, the affected gene(s) responsible for primary hypoaldosteronism other than CYP11B2 remain to be determined.

Obesity, metabolic syndrome, and insulin dynamics in children after craniopharyngioma surgery

INTRODUCTION

Children after craniopharyngioma surgery often develop rapid weight gain and hyperphagia. We investigate the metabolic syndrome features, risk factors, and the insulin dynamics in these patients.

MATERIALS AND METHODS

Standard oral glucose tolerance tests (OGTT) were performed in 12 subjects, aged 7.7-18.1 years, after surgical removal of craniopharyngioma and their healthy age-, sex-, body mass index-, and pubertal stage-matched controls. Blood samples were obtained for measurement of levels of plasma glucose, insulin, lipids, liver enzymes, baseline hormonal profiles with calculation of insulin secretion, and insulin sensitivity indices derived from OGTT.

RESULTS AND DISCUSSION

Nine of 12 subjects were severely obese. All patients exhibited significant weight gain after surgery. The waist to hip ratio was higher in subjects compared to controls (P = 0.023). Subjects had higher fasting triglycerides (P = 0.019) and lower HDL/total cholesterol ratio (P = 0.012). Five of 12 subjects met the criteria for the metabolic syndrome, compared with one of 12 in controls. One patient had prediabetes and another patient had overt type 2 diabetes. Six of 12 subjects had nonalcoholic steatohepatitis. No significant risk factors were found between each group of patients with and without the metabolic syndrome. There were no differences of insulin secretion and insulin sensitivity indices between craniopharyngioma and control subjects.

CONCLUSION

Children after craniopharyngioma surgery are at risk of rapid weight gain and the development of metabolic syndrome. Further studies to better understand the mechanism are required to design effective treatment and prevention.

Partial defect in the cholesterol side-chain cleavage enzyme P450scc (CYP11A1) resembling nonclassic congenital lipoid adrenal hyperplasia

CONTEXT

The cholesterol side-chain cleavage enzyme (P450scc), encoded by the CYP11A1 gene, converts cholesterol to pregnenolone to initiate steroidogenesis. Genetic defects in P450scc cause a rare autosomal recessive disorder that is clinically indistinguishable from congenital lipoid adrenal hyperplasia (lipoid CAH). Nonclassic lipoid CAH is a recently recognized disorder caused by mutations in the steroidogenic acute regulatory protein (StAR) that retain partial function.

OBJECTIVE

We describe two siblings with hormonal findings suggesting nonclassic lipoid CAH, who had a P450scc mutation that retains partial function.

PATIENTS AND METHODS

A 46,XY male presented with underdeveloped genitalia and partial adrenal insufficiency; his 46,XX sister presented with adrenal insufficiency. Hormonal studies suggested nonclassic lipoid CAH. Sequencing of the StAR gene was normal, but compound heterozygous mutations were found in the CYP11A1 gene. Mutations were recreated in the F2 plasmid expressing a fusion protein of the cholesterol side-chain cleavage system. P450scc activity was measured as Vmax/Km for pregnenolone production in transfected COS-1 cells.

RESULTS

The patients were compound heterozygous for the previously described frameshift mutation 835delA and the novel missense mutation A269V. When expressed in the P450scc moiety of F2, the A269V mutant retained 11% activity of the wild-type F2 protein.

CONCLUSIONS

There is a broad clinical spectrum of P450scc deficiency. Partial loss-of-function CYP11A1 mutation can present with a hormonal phenotype indistinguishable from nonclassic lipoid CAH.

Functional characterization of vasopressin receptor 2 mutations causing partial and complete congenital nephrogenic diabetes insipidus in Thai families

BACKGROUND

AVPR2 mutations cause most cases of nephrogenic diabetes insipidus (NDI); 211 AVPR2 mutations have been described, but only 7 are described causing partial NDI.

METHODS

Two unrelated Thai boys had polyuria and polydipsia in infancy but had normal electrolytes and serum osmolality at 2 years of age. Patient 1 could not concentrate his urine in response to water deprivation or 1-desamino-8-D-arginine vasopressin (DDAVP); patient 2 could concentrate to approximately 600 mosm/l. The patients' AVPR2 genes were sequenced and the identified mutations were re-created in AVPR2 cDNA expression vectors. AVPR2 activities were measured by stimulating transfected HEK293T cells with arginine vasopressin (AVP) or DDAVP, and assessing the resulting cAMP production by the activation of a luciferase reporter.

RESULTS

Patient 1 carried the previously described missense mutation R181C; patient 2 carried the novel missense mutation M311V. When transiently transfected into HEK293T cells, 6.8 x 10(-12) M AVP induced the half-maximal response (EC50) of the wild-type, whereas the EC50 value for R181C was 5.9 x 10(-9) M and for M311V was 2.6 x 10(-10)M. Responses to DDAVP were qualitatively similar but required 10-fold higher concentrations.

CONCLUSION

The novel AVPR2 mutation M311V retains partial activity and results in a milder form of NDI.

Clinical, genetic, and functional characterization of four patients carrying partial loss-of-function mutations in the steroidogenic acute regulatory protein (StAR)

CONTEXT

Nonclassic congenital lipoid adrenal hyperplasia (lipoid CAH) is a recently recognized disorder caused by mutations in the steroidogenic acute regulatory protein (StAR) that retain partial function. Affected individuals can present with a phenotype of late onset adrenal insufficiency with only mild or minimally disordered sexual development.

OBJECTIVES

The aim was to delineate the clinical spectrum of StAR mutations and correlate phenotype with StAR activity.

PATIENTS

Four patients had nonclassic/atypical lipoid CAH. Adrenal insufficiency was manifested at birth in two patients and at 11 months and 4 yr in the other two. Three were 46,XY with underdeveloped genitalia.

METHODS

The StAR gene was sequenced, mutations were recreated in expression vectors, and StAR activity was measured as pregnenolone production in COS-1 cells cotransfected with the cholesterol side-chain cleavage system. StAR mutants were expressed as N-62 StAR in bacteria, and purified proteins were tested for activity with isolated steroidogenic mitochondria and for cholesterol-binding capacity.

RESULTS

DNA sequencing identified mutations on all alleles. Missense mutations were R188C, G221D, L260P, and F267S; we also tested R192C described by others. The respective activities of R188C, R192C, G221D, L260P, and F267S were 8.0, 39.4, 2.4, 3.1, and 6.1% of wild-type in transfected cells, and 12.8, 54.8, 6.3, 1.8, and 9.5% with isolated mitochondria. Cholesterol binding capacities of R188C, R192C, G221D, L260P, and F267S were 6.7, 55.3, 10.2, 4.6, and 20.9%. These data are correlated to the three-dimensional structure of StAR.

CONCLUSIONS

There is a broad clinical spectrum of StAR mutations; StAR activities in vitro correlate well with clinical phenotypes.

Clinical, genetic, and enzymatic characterization of P450 oxidoreductase deficiency in four patients

CONTEXT

P450 oxidoreductase (POR) deficiency causes disordered steroidogenesis; severe mutations cause genital ambiguity in both sexes plus the Antley-Bixler skeletal malformation syndrome, whereas mild mutations can cause adult infertility.

OBJECTIVE

We describe four patients with POR deficiency and identify and characterize the activities of their mutations. A 46,XY male with micropenis and two 46,XX female infants with genital ambiguity presented with skeletal malformations, and a 46,XX adolescent presented with primary amenorrhea, elevated 17alpha-hydroxyprogesterone, and low sex steroids.

METHODS

The coding regions of the POR gene were sequenced, and the identified mutations were recreated in human POR cDNA expression vectors lacking 27 N-terminal residues. POR and human P450c17 were expressed in bacteria. POR activity was measured by four assays: reduction of cytochrome c, oxidation of reduced nicotinamide adenine dinucleotide phosphate, and support of the 17alpha-hydroxylase and 17,20 lyase activities of P450c17.

RESULTS

All four patients were compound heterozygotes for POR mutations, including five novel mutations: L577R, N185K, delE217, and frameshift mutations 1363delC and 697-698insGAAC. N185K and delE217 lacked measurable activity in the assays based on P450c17 but retained partial activity in the assays based on cytochrome c. As assessed by V(max)/Km, L577R supported 46% of 17alpha-hydroxylase activity but only 27% of 17,20 lyase activity. Computational modeling of these novel mutants revealed the structural basis for their reduced or absent activities.

CONCLUSION

These patients illustrate the broad clinical spectrum of POR deficiency, including amenorrhea and infertility as the sole manifestation. POR assays based on P450c17 correlate well with hormonal and clinical phenotypes.

Novel P450c17 mutation H373D causing combined 17alpha-hydroxylase/17,20-lyase deficiency

CONTEXT

Combined 17alpha-hydroxylase/17,20-lyase deficiency is a rare autosomal recessive form of congenital adrenal hyperplasia presenting with hypertension and sexual infantilism. This disorder is caused by defects in P450c17, encoded by the CYP17A1 gene.

OBJECTIVE

We describe a 14-yr-old female with clinical and hormonal features of 17alpha-hydroxylase/17,20-lyase deficiency and identify and characterize the activities of her CYP17A1 mutations.

METHODS

The coding regions of the CYP17A1 gene were amplified by PCR and sequenced. Mutations were recreated in P450c17 cDNA expression vectors; activities in transfected COS-1 cells were assayed by conversion of radiolabeled precursor steroids. One mutant was also expressed in Escherichia coli, and the reduced adsorption spectrum was measured.

RESULTS

The patient carried the previously described mutation R96W and the novel missense mutation H373D. Neither mutant had detectable activity when expressed in COS-1 cells. Membrane preparations from E. coli expressing the H373D mutant vector produced an absorption peak at 420 nm, whereas the wild-type produced a peak at 450 nm, suggesting that the H373D mutation interferes with protein folding.

CONCLUSION

The novel P450c17 mutation H373D abolished enzyme activity because of protein misfolding. These data indicate an important role for this residue in P450c17 activity.

Expanding clinical spectrum of non-autoimmune hyperthyroidism due to an activating germline mutation, p.M453T, in the thyrotropin receptor gene

OBJECTIVE

To describe clinical and genetic features of a Thai family with non-autoimmune hyperthyroidism (NAH) caused by an activating germline mutation in the thyrotropin receptor (TSHR) gene.

PATIENTS

Three affected individuals from the same family (a father and his two children) were studied. Clinical and imaging findings were reviewed and compared. GENETIC ANALYSIS: Genomic DNA was extracted from peripheral blood leukocytes and mutation analysis of the entire coding sequence of the TSHR gene was performed in both children and their parents by direct DNA sequencing.

RESULTS

A heterozygous germline T to C transition in exon 10 of the TSHR gene (c.1358T-->C) resulting in the substitution of methionine (ATG) by threonine (ACG) at codon 453 (p.M453T) was identified in the father and his two children. They presented with different clinical severity and variable age of onset. In addition to hyperthyroidism, ventriculomegaly and bilateral shortening of the fifth metacarpal bones and the middle phalanges of the fifth fingers were consistently found in all affected individuals.

CONCLUSIONS

Ventriculomegaly and bilateral shortening of the fifth metacarpal bones and the middle phalanges of the fifth fingers might be characteristic features of NAH because of an activating TSHR germline mutation. In addition, the shortening of the middle phalanges of the fifth fingers has never been previously described, expanding the phenotypic spectrum of the disease.

Bone mineral density and body composition in prepubertal and adolescent patients with the classical form of 21-hydroxylase deficiency

OBJECTIVES

To evaluate bone mineral density (BMD) and body composition in prepubertal and adolescent patients with the classical form of 21-hydroxylase deficiency.

MATERIAL AND METHOD

The authors measured height, weight and used dual energy x-ray absorptiometry (DEXA) to evaluate lumbar spine, whole body BMD and body composition in 10 prepubertal and adolescent patients with the classical form of 21-hydroxylase deficiency. Serum hormone concentrations (17-hydroxyprogesterone, dehydroepiandrosterone sulfate) were also measured. Results were compared with those of age- and sex-matched controls.

RESULTS

Seven patients were adolescent (4 girls and 3 boys; age range, 9.0-19.6 years) and three patients were prepubertal. (2 girls and 1 boy; age range, 6.5-8.6 years). There were no significant differences in age, height z-score, weight z-score and body mass index between the patients with congenital adrenal hyperplasia (CAH) and controls. DEXA showed no differences between each group in whole body BMD, but showed significantly elevated areal regional BMD at the lumbar spine (L1-L4) in CAH patients. However four of the 10 CAH patients and 6 of the 10 controls had osteopenia. The BMD z-score at the lumbar spine was significantly correlated with increasing weight z-score in both CAH patients and controls. When CAH patients with osteopenia were compared with those with normal BMD, there was a trend toward lower weight z-score, higher dose of glucocorticoids and longer duration of treatment among the osteopenic patients, but it did not reach statistical significance.

CONCLUSION

Classical 21-hydroxylase deficiency patients treated with long-term glucocorticoids did not have impaired bone mineral density compared with healthy, age and sex-matched controls. However, the reference data for BMD in the Thai pediatric population is lacking and the number of studied participants was limited so we need further studies.

Identification of two novel aquaporin-2 mutations in a Thai girl with congenital nephrogenic diabetes insipidus

OBJECTIVE

To describe a Thai girl with congenital nephrogenic diabetes insipidus (NDI) and perform mutation analysis of the AQP2 gene.

DESIGN

Case report.

PATIENT

A 6-year old girl with a history of failure to thrive, polydipsia and polyuria was studied. Polyuria and polydipsia were observed within the first few months of life. Despite normal serum osmolality and electrolyte, the result of water deprivation test was compatible with a diagnosis of NDI.

METHODS

The entire coding regions of the AQP2 gene were assessed by polymerase chain reaction and sequencing analysis. The presence of mutations was also confirmed by restriction enzyme digestion analysis.

RESULTS

Two heterozygous novel missense mutations were identified. Both were located in exon 1; a guanine-to-thymine substitution at nucleotide position 3 (c.3G-->T) inherited from her mother and a guanine-to-adenine at position 85 (c.85G-->A) inherited from her father, resulting in a methionine to isoleucine at codon 1 (p.M1I) and glycine to serine at codon 29 (p.G29S), respectively. These mutations have never been previously described and were not detected in 100 ethnic-matched unaffected control chromosomes.

CONCLUSION

We report two novel mutations of the AQP2 gene, p.M1I and p.G29S, associated with autosomal recessive congenital NDI. This study expands the genotypic spectrum of AQP2 mutations and emphasizes an important role of genetic testing for definite diagnosis and genetic counseling.

Identification of mutations in the SRD5A2 gene in Thai patients with male pseudohermaphroditism

OBJECTIVE

To describe two unrelated Thai patients with suspected 5alpha-reductase type 2 deficiency and perform mutation analysis of the SRD5A2 gene.

DESIGN

Case report.

SETTING

A pediatric endocrinology clinic at a university hospital.

PATIENT(S)

Two unrelated patients with 46,XY karyotype, born with ambiguous genitalia, were studied. One was reared as a boy and the other was reared as a girl.

INTERVENTION(S)

The entire coding regions of the SRD5A2 gene were assessed by polymerase chain reaction (PCR) and sequencing analysis.

MAIN OUTCOME MEASURE(S)

Molecular characterization of the SRD5A2 gene.

RESULT(S)

Four different pathogenic mutations (three missense and one nonsense) were identified. These were located at exon 1 (p.Q6X and p.L20P), exon 3 (p.G183S), and exon 4 (p.G203S). The T>C transition (c.59T>C) resulting in a leucine-to-proline substitution at codon 20 (p.L20P) has not been previously described and was not detected in 100 unaffected, ethnic-matched control chromosomes. In addition, p.G183S, previously identified only among patients from mixed African-European ancestry and in the Dominican Republic, was also detected in a Thai patient.

CONCLUSION(S)

This study demonstrates that the SRD5A2 gene is responsible for 5alpha-reductase type 2 deficiency across different populations and emphasizes the important role of genetic testing for the definite diagnosis and genetic counseling before gender assignment or any surgical intervention.