[show abstract][hide abstract] ABSTRACT: Hunter syndrome (or mucopolysaccharidosis type II [MPS II]) arises because of a deficiency in the lysosomal enzyme iduronate-2-sulfatase. Short stature is a prominent and consistent feature in MPS II. Enzyme replacement therapy (ERT) with idursulfase (Elaprase®) or idursulfase beta (Hunterase®) have been developed for these patients. The effect of ERT on the growth of Korean patients with Hunter syndrome was evaluated at a single center. This study comprised 32 patients, who had received ERT for at least 2 yr; they were divided into three groups according to their ages at the start of ERT: group 1 (<6 yr, n=14), group 2 (6-10 yr, n=11), and group 3 (10-20 yr, n=7). The patients showed marked growth retardation as they got older. ERT may have less effect on the growth of patients with the severe form of Hunter syndrome. The height z-scores in groups 2 and 3 revealed a significant change (the estimated slopes before and after the treatment were -0.047 and -0.007, respectively: difference in the slope, 0.04; P<0.001). Growth in response to ERT could be an important treatment outcome or an endpoint for future studies.
Journal of Korean medical science 02/2014; 29(2):254-60. · 0.84 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Mucopolysaccharidosis II (MPS II, Hunter syndrome) is a rare X-linked lysosomal storage disorder caused by the deficiency of iduronate-2-sulfatase (IDS). In affected patients, glycosaminoglycan (GAG) accumulates in the lysosomes of many organs and tissues contributing to the pathology associated with MPS II. The objective of this phase I/II clinical study was to evaluate the efficacy and safety of recombinant human iduronate-2-sulfatase (idursulfase beta, Hunterase(R)) in the treatment of MPS II. METHODS: Thirty-one MPS II patients between 6 and 35 years of age were enrolled in a randomized, single-blinded, active comparator-controlled phase I/II trial for 24 weeks. Patients were randomized to active comparator infusions (N=11), 0.5 mg/kg idursulfase beta infusions (N=10), or 1.0 mg/kg idursulfase beta infusions (N=10). The primary efficacy variable was the level of urinary glycosaminoglycan (GAG) excretion. The secondary variables were changes in the distance walked in 6 minutes (6-minute walk test, 6MWT), echocardiographic findings, pulmonary function tests, and joint mobility. RESULTS: Patients in all three groups exhibited reduction in urine GAG and this reduced GAG level was maintained for 24 weeks. Urine GAG was also significantly reduced in the 0.5 mg/kg and 1.0 mg/kg idursulfase beta groups when compared to the active comparator group (P = 0.043, 0.002, respectively). Changes in 6MWT were significantly greater in the 0.5 mg/kg and 1.0 mg/kg idursulfase groups than in the active comparator group (p= 0.003, 0.015, respectively). Both idursulfase beta infusions were generally safe and well tolerated, and elicited no serious adverse drug reactions. The most frequent adverse events were urticaria and skin rash, which were easily controlled with administration of antihistamines. CONCLUSIONS: This study indicates that idursulfase beta generates clinically significant reduction of urinary GAG, improvements in endurance as measured by 6MWT, and it has an acceptable safety profile for the treatment of MPS II.Trial registration: ClinicalTrials.gov: NCT01301898.
[show abstract][hide abstract] ABSTRACT: Precocious puberty is defined as breast development before the age of 8 years in girls. The present study aimed to reveal the diagnosis of Korean girls referred for precocious puberty and to compare the constitutional and endocrinological features among diagnosis groups.
The present study used a retrospective chart review of 988 Korean girls who had visited a pediatric endocrinology clinic from 2006 to 2010 for the evaluation of precocious puberty. Study groups comprised fast puberty, true precocious puberty (PP), pseudo PP, premature thelarche, and control. We determined the height standard deviation score (HSDS), weight standard deviation score (WSDS), and body mass index standard deviation score (BMISDS) of each group using the published 2007 Korean growth charts. Hormone tests were performed at our outpatient clinic.
The PP groups comprised fast puberty (67%), premature thelarche (17%), true PP (15%), and pseudo PP (1%). Advanced bone age and levels of estradiol, basal luteinizing hormone (LH), and peak LH after gonadotropin-releasing hormone stimulation testing were significantly high in the fast puberty and true PP groups compared with the control group. HSDS, WSDS, and BMISDS were significantly higher in the true PP group than in the control group (P<0.05).
The frequent causes of PP were found to be fast puberty, true PP, and premature thelarche. Furthermore, BMISDS were significantly elevated in the true PP group. Therefore, we emphasize the need for regular follow-up of girls who are heavier or taller than others in the same age group.
Korean Journal of Pediatrics 12/2012; 55(12):481-6.
[show abstract][hide abstract] ABSTRACT: Single-nucleotide polymorphism (SNP) markers within LIN28B have been reported to be related to the timing of pubertal growth. However, no study has investigated the frequency of genetic markers in girls with precocious puberty (PP) or early puberty (EP). This study aimed to determine the frequency of putative genetic markers in girls with PP or EP.
Genomic DNAs were obtained from 77 and 109 girls that fulfilled the criteria for PP and EP, respectively. The controls in this study were 144 healthy volunteers between 20 and 30 years of age. The haplotypes were reconstructed using 11 SNPs of LIN28B, and haplotype association analysis was performed. The haplotype frequencies were compared. Differences in the clinical and laboratory parameters were analyzed according to the haplotype dosage.
Eleven SNPs in LIN28B were all located in a block that was in linkage disequilibrium. The haplotype could be reconstructed using 2 representative SNPs, rs4946651 and rs369065. The AC haplotype was less frequently observed in the PP group than in the controls (0.069 vs. 0.144, P=0.010). The trend that girls with non-AC haplotypes tended to have earlier puberty onset (P=0.037) was illustrated even in the EP+PP patient group by Kaplan-Meier analysis.
The results of the present study showed that non-AC haplotypes of LIN28B had a significant association with PP in girls.
Korean Journal of Pediatrics 10/2012; 55(10):388-92.
[show abstract][hide abstract] ABSTRACT: Continuous renal replacement therapy (CRRT) is becoming the treatment of choice for supporting critically ill pediatric patients. However, a few studies present have reported CRRT use and outcome in neonates weighing less than 3 kg. The aim of this study is to describe the clinical application, outcome, and complications of CRRT in small neonates.
A retrospective review was performed in 8 neonatal patients who underwent at least 24 hours of pumped venovenous CRRT at the Samsung Medical Center in Seoul, Korea, between March 2007 and July 2010. Data, including demographic characteristics, diagnosis, vital signs, medications, laboratory, and CRRT parameters were recorded.
The data of 8 patients were analyzed. At the initiation of CRRT, the median age was 5 days (corrected age, 38(+2) weeks to 23 days), and the median body weight was 2.73 kg (range, 2.60 to 2.98 kg). Sixty-two patient-days of therapy were reviewed; the median time for CRRT in each patient was 7.8 days (range, 1 to 37 days). Adverse events included electrolyte disturbances, catheter-related complications, and CRRT-related hypotension. The mean circuit functional survival was 13.9±8.6 hours. Overall, 4 patients (50%) survived; the other 4 patients, who developed multiorgan dysfunction syndrome, died.
The complications of CRRT in newborns are relatively high. However, the results of this study suggest that venovenous CRRT is feasible and effective in neonates weighing less than 3 kg under elaborate supportive care. Furthermore, for using potential benefit of CRRT in neonates, efforts are required for prolonging filter survival.
Korean Journal of Pediatrics 08/2012; 55(8):286-92.
[show abstract][hide abstract] ABSTRACT: Mucopolysaccharidosis (MPS) II is an X-linked metabolic disorder caused by dysfunction of iduronate-2-sulfatase (I2S). This abnormality causes the progressive accumulation of incompletely degraded glycosaminoglycans (GAGs) in the lysosomes. The auditory characteristics of MPS II in mouse models have not been reported. In this study, we evaluated the auditory characteristics of the MPS II in IDS knock-out (IDS-KO) mice. In addition, the effect of enzyme replacement therapy (ERT) on hearing was studied. The IDS-KO mice had normal histology of the cochlea and retained good hearing at 7 weeks of age. However, at 17 weeks of age, the hearing thresholds of the IDS-KO mice were elevated and exudates were found in the middle ear. The hearing thresholds of the enzyme-treated IDS-KO (IDS-ERT) mice were similar to the wild-type (WT) mice at 17 weeks. Moreover, the microstructure of the inner ear was similar to the IDS-KO by transmission electron microscopy. The histology findings indicated that the microstructure of the inner ear was similar in comparisons between IDS-KO and IDS-ERT mice, even after 10 weeks of treatment. However, the hearing deficits in the MPS II mouse model can be prevented if ERT is started before the onset of hearing impairment.
American Journal of Medical Genetics Part A 07/2012; 158A(9):2131-8. · 2.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: Patients with Xp deletions have short stature and may have some somatic traits typical of Turner syndrome (TS), whereas gonadal function is generally preserved. In most studies of these patients, microsatellites have been used to determine the break point of the Xp deletion. In the present study, we describe the clinical, cytogenetic, and chromosomal microarray (CMA) analysis of a family with an Xp22.33-Xp22.12 deletion. Two female siblings, aged 8 years 9 months and 11 years 10 months, presented with short stature. The older sibling's height (index case) was 137.9 cm (-1.81 SDS) and the younger sibling's height was 118.6 cm (-2.13 SDS). The mother and both daughters had only a short stature; a skeletal survey showed normal findings except for mildly shortened 4th and 5th metacarpal bones. No features of TS were present. The deletion appeared terminal with a breakpoint within Xp22.2 located about 19.9 Mb from the Xp telomere. The deletion contained 102 protein-coding genes. A probe of the end breakage point was located at the 19,908,986th base of the X chromosome, and a probe of the marginal normal region near the breakage point was located at the 19,910,848th base of the X chromosome. Therefore, the breakage point was concluded to be located between these two probes. In summary, we report a familial case of an Xp deletion. The findings of our study may be helpful in further analyzing the phenotypes associated with Xp deletions.
American Journal of Medical Genetics Part A 05/2012; 158A(6):1462-6. · 2.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: Rabson-Mendenhall syndrome (RMS) is a rare syndrome manifested by extreme insulin resistance with hyperinsulinemia, acanthosis nigricans, tooth dysplasia and growth retardation. Our patient was first noted at the age of 8 months due to pigmentations on skin-folded areas. Initial laboratory tests showed normal fasting glucose (69 mg/dL). Fasting insulin level was severely elevated, up to 554.6 µIU/mL, and c-peptide level was increased, up to 13.81 ng/mL. However, hemoglobin A1c was within normal range (4.8%). He is now 11 yr old. His growth development followed the 5-10th percentile and oral hypoglycemic agents are being administered. The last laboratory results showed insulin 364.1 µIU/mL, C-peptide 4.30 ng/mL, and hemoglobin A1c 7.6%. The boy was a compound heterozygote for the c.90C > A and c.712G > A mutations of the insulin receptor gene, INSR, which are nonsense and missense mutations. In summary, we report the first Korean case of RMS, which was confirmed by two novel mutations of the INSR.
Journal of Korean medical science 05/2012; 27(5):565-8. · 0.84 Impact Factor
[show abstract][hide abstract] ABSTRACT: Mucopolysaccharidosis type VI (MPS VI; Maroteaux-Lamy syndrome, OMIM #253200) is a rare disorder involving multiple organs and manifested particularly by severe skeletal abnormalities. Bone marrow transplantation (BMT) improves cardiopulmonary function and facial features, but has limited success in ameliorating skeletal abnormalities and short stature. Here, we report the outcome of enzyme replacement therapy (ERT) with recombinant human arylsulfatase-B (ASB, Naglazyme, BioMarin, Novato, CA) in an MPS VI patient who received BMT 10 years prior to ERT induction. Administration of weekly Naglazyme for 18 months was effective in improving range of motion in several joints [shoulders (improvement of flexion (Right/Left): 40°/55°; improvement of extension 30°/40°; improvement of abduction 10°/10°), elbows (improvement of flexion 25°/25°; improvement of extension 10°/15°), hips (improvement of flexion 25°/10°), and knees (improvement of flexion 45°/40°; improvement of extension 50°/60°)]. Improvement in the outcome of the 12-min walk test (70% increase) and 3-min stair-climbing test (29% increase) was also noted after ERT. Because ERT improved clinical features in an MPS VI patient who had undergone prior BMT, the role of ERT post successful BMT in MPS VI needs further investigation.
American Journal of Medical Genetics Part A 04/2012; 158A(5):1158-63. · 2.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: Mucopolysaccharidosis type II (MPS II or Hunter syndrome) is a rare lysosomal storage disorder caused by iduronate-2-sulfatase (IDS) deficiency. MPS II causes a wide phenotypic spectrum of symptoms ranging from mild to severe. IDS activity, which is measured in leukocyte pellets or fibroblasts, was reported to be related to clinical phenotype by Sukegawa-Hayasaka et al. Measurement of residual plasma IDS activity using a fluorometric assay is simpler than conventional measurements using skin fibroblasts or peripheral blood mononuclear cells. This is the first study to describe the relationship between plasma IDS activity and clinical phenotype of MPS II.
We hypothesized that residual plasma IDS activity is related to clinical phenotype. We classified 43 Hunter syndrome patients as having attenuated or severe disease types based on clinical characteristics, especially intellectual and cognitive status. There were 27 patients with the severe type and 16 with the attenuated type. Plasma IDS activity was measured by a fluorometric enzyme assay using 4-methylumbelliferyl-α-iduronate 2-sulphate.
Plasma IDS activity in patients with the severe type was significantly lower than that in patients with the attenuated type (P=0.006). The optimal cut-off value of plasma IDS activity for distinguishing the severe type from the attenuated type was 0.63 nmol·4 hr(-1)·mL(-1). This value had 88.2% sensitivity, 65.4% specificity, and an area under receiver-operator characteristics (ROC) curve of 0.768 (ROC curve analysis; P=0.003).
These results show that the mild phenotype may be related to residual lysosomal enzyme activity.
Korean Journal of Pediatrics 03/2012; 55(3):88-92.
[show abstract][hide abstract] ABSTRACT: Mutations in the GLB1 gene, which encodes acid β-galactosidase, can result in two disease phenotypes: GM1-gangliosidosis (MIM #230500) and Morquio B disease (Mucopolysaccharidosis type IVB, MIM #253010). Morquio B disease occurs much more infrequently than GM1-gangliodosis and is characterized by severe skeletal manifestations (dysostosis multiplex) without central nervous system involvement. Here, we report the first known Korean patient with Morquio B disease. A 7-year-old boy presented with severe progressive skeletal dysplasia including scoliosis, contractures of the elbows, xenu valgum, funnel chest, and trigger thumb requiring surgical intervention. The patient had normal neurological functions and mental status when evaluated by pediatric neurologists. The patient's urinary glycosaminoglycans, measured by the cetylpyridinium chloride (CPC) precipitation test, were 252.8 CPC unit/g creatinine (reference range < 175). Thin layer chromatography of urine showed a keratan sulfate band. Enzyme activity of β-galactosidase in leukocytes was 1.15 nmol/hr/mg protein (reference range 78.1-117.7; 1-1.5% of normal). The patient had compound heterozygous mutations of the GLB1 gene: c.13_14insA (p.L5HfsX29), which was reported in a patient with infantile GM1 gangliosidosis with the near-complete absence of enzyme activity, and c.367G>A (p.G123R), which is a novel frame-shift mutation. In summary, we report the first known Korean patient with Morquio B disease and a novel mutation (c.13_14insA of GLB1).
Annals of clinical and laboratory science 01/2012; 42(1):89-93. · 0.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Tricho-rhino-phalangeal syndrome type I (TRPSI) is a rare autosomal dominant hereditary disorder characterized by sparse hair, bulbous nose, long philtrum, thin upper lip, and skeletal abnormalities including cone-shaped epiphyses, shortening of the phalanges, and short stature. TRPSI is caused by mutations in the TRPS1 gene. Herein, we report two Korean cases of TRPSI. Although both patients (a 17-year-old-female and a 14-year-old male) had typical clinical findings, Patient 1 had an additional growth hormone (GH) deficiency. Treatment with recombinant human growth hormone (rhGH) 0.7 IU/kg/week led to an increase in growth velocity. Over 10 years of GH therapy, the mean growth velocity was 5.7±0.9 cm/year. However, the patient 2 did not show apparent GH deficiency by GH stimulation test, had a poor response with rhGH therapy and GH therapy was discontinued after 6 months. Upon genetic analysis of the TRPS1 gene, two mutations were found. Patient 1 had a heterozygous mutation c.2520dupT (p.Arg841LysfsX3) which had not been previously reported. Patient 2 had a known nonsense mutation c.1630C>T (p.Arg544X). In summary, we were the first to report Korean patients with mutation of TRPS1.
Annals of clinical and laboratory science 01/2012; 42(3):307-12. · 0.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: The exon-3 deletion polymorphism (d3, Database of Genomic Variants ID: Variation_64191) in the growth hormone receptor (GHR) gene is associated with increased growth response to growth hormone (GH) therapy in GH-deficient patients. However, an association of the GHR genotype with height has not yet been reported in Prader-Willi syndrome (PWS). The aim of this study was to assess the association of GHR alleles with height before starting GH therapy in patients with PWS. Seventy-four patients with PWS were genotyped and their medical records were retrospectively reviewed (45 males and 29 females, median age 8.7 years). One hundred normal controls, with known final height, were also genotyped. The GH-exon 3 locus was genotyped using a PCR multiplex assay. The distribution of alleles in the patients with PWS was not different from controls [(fl/fl n = 53 (72%), fl/d3 n = 21 (28%)) in PWS vs. (fl/fl n = 72(72%), fl/d3 n = 26(26%), and d3/d3 n = 2(2%)]. However, patients with PWS carrying a d3 allele had significantly greater height standard deviation scores (SDS) (P = 0.025) and higher insulin-like growth factor I (IGF-I) level (P = 0.041), although the age at the start of GH therapy, weight, BMI, and body fat were not different. The d3 allele was associated with height and IGF-I levels before GH therapy and suggests that even before GH therapy, d3 allele may influence height through GH secretion.
American Journal of Medical Genetics Part A 11/2011; 155A(12):2970-3. · 2.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: This paper proposes a novel method that preserves the geometrical structure created by variation of multiple factors in analysis of multiple factor models, i.e., multifactor analysis. We use factor-dependent submanifolds as constituent elements of the factor-dependent geometry in a multiple factor framework. In this paper, a submanifold is defined as some subset of a manifold in the data space, and factor-dependent submanifolds are defined as the submani-folds created for each factor by varying only this factor. In this paper, we show that MPCA is formulated using factor-dependent submanifolds, as is our proposed method. We show, however, that MPCA loses the original shapes of these submanifolds because MPCA's parameterization is based on averaging the shapes of factor-dependent subman-ifolds for each factor. On the other hand, our proposed multifactor analysis preserves the shapes of individual factor-dependent submanifolds in low-dimensional spaces. Because the parameters obtained by our method do not lose their structures, our method, unlike MPCA, sufficiently covers original factor-dependent submanifolds. As a result of sufficient coverage, our method is appropriate for accurate classification of each sample.
[show abstract][hide abstract] ABSTRACT: Although carpal tunnel syndrome (CTS) is the most common compressive neuropathy seen in the upper extremity of adults, it is rarely seen in children. Several reports have shown that mucopolysaccharidosis type II (Hunter syndrome), a rare genetic disorder, is one of the causes of CTS in children. Usual symptoms of CTS are pain, weakness, and paresthesias in the hand and digits. However, the diagnosis of CTS in Hunter syndrome is often delayed or unrecognized because of atypical symptoms and cognitive impairment. Here, we report the prevalence, clinical manifestation, and nerve conduction profiles of CTS in 45 Hunter syndrome patients. The mean age of the study participants was 117.1 (74.9) months (range: 4-408 months); all patients were male. Forty-three (96.0%) of the 45 patients with Hunter syndrome had CTS. Bilateral CTS was observed in all patients; 73 (82.0%) of the patients' hands had severe degree of CTS. Intriguingly, in contrast with other nerve velocities, decreases in forearm conduction velocities of the median nerve were observed in 28 (31.5%) of 89 hands with CTS. There was a significant difference in age (P < 0.001) between hands with normal, mild, moderate, and severe grades of CTS. The compound muscle action potential and sensory nerve action potential amplitudes of the median nerves decreased with age (CMAP, r = -0.526, P < 0.001; SNAP, r = -0.564, P < 0.001). Early recognition and intervention to ameliorate the symptoms of CTS are important in improving the quality of life of Hunter syndrome patients.
American Journal of Medical Genetics Part A 06/2011; 155A(6):1329-35. · 2.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: Long-term survivors of childhood cancer appear to have an increased risk for the metabolic syndrome, subsequent type 2 diabetes and cardiovascular disease in adulthood compared to healthy children. The purpose of this study was to investigate the frequency of the metabolic syndrome and associated factors in childhood cancer survivors at a single center in Korea.
We performed a retrospective review of medical records of 98 childhood cancer survivors who were diagnosed and completed anticancer treatment at Samsung Medical Center, Seoul, Korea between Jan. 1996 and Dec. 2007. Parameters of metabolic syndrome were evaluated between Jan. 2008 and Dec. 2009. Clinical and biochemical findings including body fat percentage were analyzed.
A total of 19 (19.4%) patients had the metabolic syndrome. The median body fat percentage was 31.5%. The body mass index and waist circumference were positively correlated with the cranial irradiation dose (r=0.38, P<0.001 and r=0.44, P<0.00, respectively). Sixty-one (62.2%) patients had at least one abnormal lipid value. The triglyceride showed significant positive correlation with the body fat percentage (r=0.26, P=0.03). The high density lipoprotein cholesterol showed significant negative correlation with the percent body fat (r=-0.26, P=0.03).
Childhood cancer survivors should have thorough metabolic evaluation including measurement of body fat percentage even if they are not obese. A better understanding of the determinants of the metabolic syndrome during adolescence might provide preventive interventions for improving health outcomes in adulthood.
Korean Journal of Pediatrics 06/2011; 54(6):253-9.
[show abstract][hide abstract] ABSTRACT: Amylin secretion is increased parallel to insulin in obese subjects. Despite their marked obesity, a state of relative hypoinsulinemia occurs in children with Prader-Willi syndrome (PWS). Based on the hypothesis that amylin levels may be relatively low in PWS children, contributing to their excessive appetite, we studied amylin levels after oral glucose loading in children with PWS and overweight controls.
Plasma levels of amylin, glucagon, insulin, and glucose were measured at 0, 30, 60, 90, and 120 min after a glucose challenge in children with PWS (n = 18) and overweight controls (n = 25); the relationships among the variables were investigated in these two groups.
Amylin levels were significantly correlated with insulin during fasting and during the oral glucose tolerance test in both groups. Amylin levels between 0 and 60 min after glucose loading were statistically different between the two groups. They were lower in children with PWS than in the controls between 0 and 30 min after glucose loading.
The relatively low levels of amylin, compared to those in overweight controls, during the early phase of glucose loading in patients with PWS, may contribute, in part, to the excessive appetite of PWS patients as compared to the overweight controls.
Yonsei medical journal 03/2011; 52(2):257-62. · 0.77 Impact Factor