Byung-Kyu Suh

High allele frequency of the p.Q258X mutation and identification of a novel mis-splicing mutation in the STAR gene in Korean patients with congenital lipoid adrenal hyperplasia.

OBJECTIVE Steroidogenic acute regulatory (STAR) protein plays a crucial role in steroidogenesis, and mutations in the STAR gene cause congenital lipoid adrenal hyperplasia (CLAH). This study investigated the STAR mutation spectrum and functionally analyzed a novel STAR mutation in Korean patients with CLAH. METHODS Mutation analysis of STAR was carried out in 25 unrelated Korean CLAH patients. A region of STAR comprising exons 4-7 was cloned from human genomic DNA into an expression vector, followed by site-directed mutagenesis and transient expression in COS7 cells. The splicing pattern was analyzed by in vitro transcription, and each transcript was functionally characterized by measuring pregnenolone production in COS7 cells cotransfected with the cholesterol side chain cleavage system. RESULTS Mutation p.Q258X was identified in 46 of 50 alleles (92%); mutation c.653C>T was detected in two alleles (4%); and mutations p.R182H and c.745-6_810del were found in one allele (2%). Reverse transcriptase-PCR products amplified from a patient heterozygous for compound c.653C>T and c.745-6_810del mutation revealed multiple alternatively spliced mRNAs. In vitro expression analysis of a minigene consisting of exons 4-7 containing the c.653C>T yielded two transcripts in which exon 6 or exons 5 and 6 were skipped. The encoded proteins exhibited defective pregnenolone-producing ability. The c.745-6_810del mutation led to full and partial intron retention. CONCLUSIONS p.Q258X is the most common STAR mutation in Korea. A previously reported c.653C>T variant was found to cause aberrant splicing at the mRNA level, resulting in perturbation of STAR function. The c.745-6_810del mutation also resulted in aberrant splicing.

Association of HLA Alleles with Autoimmune Thyroid Disease in Korean Children

Backgrounds: Data regarding genetics of Hashimoto’s disease (HD) and Graves’ disease (GD) in Korean children are lacking. Methods: 73 patients with autoimmune thyroid disease (AITD; HD 32, GD 41) were recruited. We analyzed human leukocyte antigen (HLA) class I and HLA-DRB1 by PCR-SSP, and compared them with those of 159 controls. Results: In AITD, the allele frequencies of HLA-A*02, -B*46, -Cw*01 and -DRB1*08 were higher and those of HLA-A*30, -B*07, -Cw*07 and -DRB1*01 were lower than in controls. In HD, those of HLA-B*46 and -Cw*01 were higher and those of HLA-DRB1*01 and -Cw*07 were lower than in controls. In GD, those of HLA-A*02, -B*46, -Cw*01 and -DRB1*08 were higher and those of HLA-DRB1*07 and -Cw*07 were lower than in controls. Between HD and GD, there were no significant differences in allele frequencies. The risk of AITD in the presence of both HLA-B*46 and -Cw*01 is higher than in the presence of either allele alone. Conclusion: The susceptible and protectable alleles in HD are similar to those in GD. Coexistence of HLA-B*46 and -Cw*01 may be a genetic gene marker for early-onset AITD in Koreans.

Serum ferritin level is higher in male adolescents with obesity: results from the Korean National Health and Nutrition Examination Survey 2010.

Purpose Previous reports show an association between high serum ferritin levels and metabolic syndrome (MS) in adults. In adolescents, little information is available with obesity and serum ferritin levels. Methods This is a cross-sectional study. Data were obtained from the 5th Korean National Health and Nutrition Examination Survey (K-NHANES) conducted during 2010 by the Korean Ministry of Health and Welfare. A total of 849 subjects aged 10-18 years participated in the 2010 survey. A body mass index (BMI) ≥95th percentile for age and sex or a BMI ≥25 was used to diagnose as obesity. Results The weighted prevalence of obesity was 13.4% (62/462) in male and 8.5% (33/387) in female. We observed significantly higher serum ferritin in male than in female (mean±standard error [SE], 50.5±2.3 µU/L vs. 30.6±1.3 µU/L; P<0.0001). In male, serum ferritin is positively correlated with age (P<0.0001). White blood cell (WBC) count, serum fasting blood sugar, triglyceride (TG), total cholesterol, low-density lipoprotein, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), systolic and diastolic blood pressure, and ferritin levels were higher and high-density lipoprotein (HDL) were lower in the obesity than in the normal group. In female adolescents, WBC count, TG, insulin, and HOMA-IR were higher and HDL were lower in the obesity than in the normal group. In male, serum ferritin levels showed positive association with obesity (β=21.196, P=0.016). Conclusion Serum ferritin levels appear to be associated with obesity in Korean male adolescents.

Association of MICA Alleles with Autoimmune Thyroid Disease in Korean Children

Background. Major histocompatibility complex class I chain-related gene A (MICA) is a ligand for the activating NKG2D receptor expressed on natural killer (NK) cells. We aimed to assess the association of MICA polymorphism with autoimmune thyroid disease (AITD) in Korean children. Methods. Eighty-one patients with AITD were recruited. We analyzed MICA polymorphisms by PCR-SSP and compared the results with those of 70 healthy controls. Results. In AITD, the allele frequencies of MICA∗010 (OR = 2.21; 95% CI, 1.30–3.76, P < 0.003, P c < 0.042) were higher than those of controls. Patients who did not have thyroid-associated ophthalmopathy showed higher frequencies of MICA∗010 (OR = 2.99; 95% CI, 1.47–6.08, P < 0.003, P c < 0.042) and lower frequencies of MICA∗008 (OR = 0.08; 95% CI, 0.01–0.62, P < 0.001, P c < 0.014) compared to those of controls. HLA-B∗46, which shows the strongest association with AITD compared with other HLA alleles, showed the strongest linkage disequilibrium with MICA∗010. Analyses of the associations between MICA∗010 and HLA-B∗46 with AITD suggest an association of the MICA allele with AITD. Conclusions. Our results suggest that innate immunity might contribute to the pathogenesis of AITD.

Primary ovarian dysfunction after hematopoietic stem cell transplantation during childhood: busulfan-based conditioning is a major concern.

Abstract We evaluated the incidence of patient/treatment factors associated with primary ovarian failure (POF) after hematopoietic stem cell transplantation (HSCT) during childhood. Fifty girls over 12 years of age (15.0±2.2) who were referred to the pediatric endocrinology clinic between March 2002 and March 2010 after HSCT at the Catholic HSCT center were enrolled in the study. In total, 36 (72%) out of 50 patients developed POF. Twenty-three patients were diagnosed and treated as chronic graft-versus-host disease. As preparative regimens for HSCT, 23 patients received total body irradiation (TBI)-based regimen, 19 received busulfan (BU)-based regimen, 4 received both BU- and TBI-based, and 4 received reduced intensity conditioning regimen. In a univariate logistic regression analysis, the BU-based regimen (p=0.028) showed a strong relationship with POF. The incidence of POF according to the route of BU administration, between orally and intravenously, were not different (p=0.435). These results emphasize the importance of monitoring these patients at regular intervals and the need to develop complementary HSCT protocols for preventing POF in children.

Insulin Resistance of Normal Weight Central Obese Adolescents in Korea Stratified by Waist to Height Ratio: Results from the Korea National Health and Nutrition Examination Surveys 2008–2010

Background. To evaluate insulin resistance of normal weight central obese 13–18-year-old male and female adolescents stratified by waist to height ratio (WHR). Methods. Data were obtained from the Korea National Health and Nutrition Examination Survey (K-NHANES) conducted during 2008–2010. Central obesity was defined as that in the upper quartile of age and sex specific WHR. Subjects were classified into no central obesity normal weight (NW), central obesity normal weight (CONW), no central obesity overweight (OW), and central obesity overweight (COOW). Results. The prevalence of CONW was 9.6% (83/832) in female and 7.0% (61/909) in male. CONW showed higher levels of insulin (P < 0.006), HOMA-IR (P < 0.006), and ALT (P < 0.001) than NW in female. CONW had higher levels of insulin (P < 0.0001), HOMA-IR (P < 0.0001), and WBC count (P < 0.021) and lower level of HDL (P < 0.0001) than NW in male. WHR and BMI had similar significant correlations with MS components. CONW showed 2.5 times (95% confidence interval, 1.21–5.00) more likelihood to have high insulin resistance than NW in male. Conclusions. Screening for central obesity using WHR in clinical setting is recommended.

Growth without growth hormone in combined pituitary hormone deficiency caused by pituitary stalk interruption syndrome

Growth hormone (GH) is an essential element for normal growth. However, reports of normal growth without GH have been made in patients who have undergone brain surgery for craniopharyngioma. Normal growth without GH can be explained by hyperinsulinemia, hyperprolactinemia, elevated leptin levels, and GH variants; however, its exact mechanism has not been elucidated yet. We diagnosed a female patient aged 13 with combined pituitary hormone deficiency (CPHD) caused by pituitary stalk interruption syndrome (PSIS). The patient has experienced recurrent hypoglycemic seizures since birth, but reached the height of 160 cm at the age of 13, showing normal growth. She grew another 8 cm for 3 years after the diagnosis, and she reached her final adult height of 168 cm which was greater than the midparental height, at the age of 16. The patients blood GH and insulin-like growth factor-I levels were consistently subnormal, although her insulin levels were normal. Her physical examination conducted at the age of 15 showed truncal obesity, dyslipidemia, and osteoporosis, which are metabolic features of GH deficiency (GHD). Herein, we report a case in which a PSIS-induced CPHD patient attained her final height above mid parental height despite a severe GHD.

Current growth status and metabolic parameters of Korean adolescents born small for gestational age: Results from the Korea National Health and Nutrition Examination Surveys (KNHANES) 2010–2011

Currently, little information is available on current growth status and metabolic syndrome (MetS) components according to birthweight at gestational age (BWGA) on Korean adolescents. Herein, the current height and weight and MetS components of Korean adolescents who were born as small for gestational age (SGA) were compared to those of the appropriate for GA (AGA) or large for GA (LGA) groups.

Risk factors for short term thyroid dysfunction after hematopoietic stem cell transplantation in children

Purpose The purpose of this study was to evaluate short-term thyroid dysfunction and related risk factors in pediatric patients who underwent hematopoietic stem cell transplantation (HSCT) during childhood. Methods We studied 166 patients (100 boys and 66 girls) who underwent HSCT at the Catholic HSCT Center from January 2004 through December 2009. The mean age at HSCT was 10.0±4.8 years. Thyroid function of the patients was tested before and during 3 months of HSCT. Results Out of 166 patients, 165 (99.4%) underwent allotransplantation. Acute graft-versus-host disease (GVHD, grades II to IV) developed in 76 patients. Conditioning regimens before HSCT include total body irradiation (n=57), busulfan (n=80), and reduced intensity (n=29). Forty-five (27.1%) had thyroid dysfunction during 3 months after HSCT (29 euthyroid sick syndrome [ESS], 6 subclinical hyperthyroidism, 4 subclinical hypothyroidism, 3 hypothyroxinemia, 2 overt hyperthyroidism, and 1 high T4 syndrome). In a univariate logistic regression analysis, age at HSCT (P=0.002) and acute GVHD (P=0.009) had statistically significant relationships with thyroid dysfunction during 3 months after HSCT. Also, in a univariate logistic regression analysis, ESS (P=0.014) showed a strong statistically significant association with mortality. Conclusion In our study 27.1% patients experienced thyroid dysfunction during 3 months after HSCT. Increase in age and acute GVHD may be risk factors for thyroid dysfunction during 3 months after HSCT. There was a significant association between ESS and mortality.

Two cases of Shwachman-Diamond syndrome in adolescents confirmed by genetic analysis.

Dear Editor, Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder (OMIM 260400) characterized by exocrine pancreatic insufficiency, skeletal abnormalities, and hematologic dysfunction, with up to 30% risk of developing MDS. The SBDS gene (OMIM 607744) maps to chromosome 7q11.21, and 90% of SDS patients possess mutations of this gene [1]. To date, three SDS cases have been reported in Korea, and only one has been confirmed on the basis of SBDS genetic analysis [2, 3, 4] (Table 1). We describe two cases of unrelated Korean adolescent SDS patients. We received approval from the Institutional Review Board of Seoul St. Marys Hospital. Table 1 Clinical features of SDS patients reported in Korea A boy of 13 yr and 9 months underwent a corticotomy of the right femur and external fixation with the Ilizarov method to correct a genu valgum orthopedic deformity. While hospitalized, congenital lipomatosis of the pancreas was unexpectedly observed in an abdominal computed tomography (CT) scan for hisdyspepsia. There were no abnormal findings in his birth, family, and sibling histories. He was the younger of the two children. A brain magnetic resonance imaging (MRI) for failure to thrive (FTT) at 6 months old, growth hormone stimulation test, chromosomal analysis, and chromosomal breakage test conducted for short stature at 11 yr old and newly observed neutropenia at 13 yr old were normal. At diagnosis, the weight and height of the patient were each below the 3rd percentile (35 kg and 139 cm). The results of a peripheral blood (PB) examination were as follows: leukocyte count, 3.31×109/L (neutrophils 5%, lymphocytes 88%, monocytes 5%, and eosinophils 0%); hemoglobin, 12.3 g/dL (mean cell volume [MCV] 90.7 fL); platelet count, 109×109/L; Hb F, 1.2%. Low digestive enzyme levels with respect to amylase were found (52 U/L, normal range: 48-176 U/L), lipase was 4.0 U/L (7.0-50.0 U/L) and trypsin was less than 50 ng/mL (110-460 ng/mL). A boy of 15 yr and 6 months was accidently diagnosed as having congenital lipomatosis of the pancreas by CT scan in the course of a differential diagnosis of appendicitis. There were no abnormal findings in the birth, family, and sibling histories, and he was the youngest child of three boys. He had been followed up for mild cytopenia without transfusion in another hospital since 12 months of age, and valgus osteotomy was done for congenital coxa vara at 7 yr of age. At diagnosis, the patient was below the 3rd percentile for height and 10th percentile for weight (48 kg and 154.8 cm). The results of a PB examination were as follows: leukocytes, 3.68×109/L (neutrophils 33%, lymphocytes 56%, monocytes 10%, and eosinophils 1%); hemoglobin, 13.6 g/dL (MCV 95 fL); platelet count, 103×109/L; and Hb F, 1.8%. A low level of amylase (30 U/L, normal range: 48-176 U/L) was observed, and lipase (23.8 U/L, 7.0-50.0 U/L) and trypsin (200 ng/mL, 110-460 ng/mL) were within the normal ranges. Genomic DNA was isolated from PB leukocytes by using the QIAamp DNA Mini Kit (Qiagen, Hamburg, Germany). PCR was carried out by using gene-specific primers for exon2 of SBDS [5]. Since an unprocessed pseudogene, SBDSP, resides in a locally duplicated genomic segment of 305 kb [6], the specificities of the primers were checked by using Primer-BLAST (http://www.ncbi.nlm.nih.gov.proxy.cuk.ac.kr:8080/tools/primer-blast) and also in 10 normal controls. All mutations were described according to the Human Genome Variation Society nomenclature [7]. RefSeq ID: NM_ 016038.2 was used for the alignment. Direct sequencing of the PCR products revealed two heterozygous mutations, c.183_ 184TA>CT and c.258+2T>C, for Case 1 and a homozygous mutation c.[258+2T>C];[258+2T>C] for Case 2 (Fig. 1). Fig. 1 The chromatograms of SBDS mutations in the present SDS cases. (A) Case 1: Sequencing chromatograms of subcloned PCR products demonstrate the compound heterozygosity of c.258+2T>C (A1) and c.183_184TA>CT (A2) mutations. (B) Case 2: Direct ... We subcloned the PCR products with a TOPO TA Cloning Kit (Invitrogen, Carlsbad, CA, USA) and sequenced the products to confirm the zygosity of the mutations in Case 1. Direct sequencing of the cloned PCR products demonstrated that the two heterozygous mutations were compound heterozygous, c.[183_ 184TA>CT];[258+2T>C]. SDS is the second most common cause of inherited exocrine pancreatic dysfunction in children. A short stature seemed to be caused by intrinsic factors of SDS and risk factors such as malabsorption, delayed puberty, and infections [8]. The most frequently reported mutation type, c.[183_ 184TA>CT], forms in-frame stop codons, while c.[258+2T>C] forms truncated proteins by the destruction of donor splice sites [6]. Based on the guidelines proposed by Dror et al. [9], there was no single test to confirm the diagnosis. Genotyping may be used for diagnostic confirmation, but a negative test for SBDS mutations does not exclude the diagnosis, given that 10% of SDS individuals showed no SBDS mutations [10]. An early diagnosis of SDS is necessary to monitor the risk of hematologic malignancy and supplementary therapy for clinical symptoms.