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Purpose Pompe disease (PD) is an autosomal recessive disorder caused by a deficiency of acid alphaglucosidase resulting from pathogenic GAA variants. This study describes the clinical features, genotypes, changes before and after enzyme replacement therapy (ERT), and long-term outcomes in patients with infantile-onset PD (IOPD) and late-onset PD (LOPD) at a tertiary medical center. Methods The medical records of 5 Korean patients (2 male, 3 female patients) diagnosed with PD between 2002 and 2013 at Samsung Medical Center in Seoul, Republic of Korea were retrospectively reviewed for data, including clinical and genetic characteristics at diagnosis and clinical course after ERT. Results Common initial symptoms included hypotonia, cyanosis, and tachycardia in patients with IOPD and limb girdle weakness in patients with LOPD. Electrocardiography at diagnosis revealed hypertrophic cardiomyopathy in all patients with IOPD who showed a stable disease course during a median follow-up period of 10 years. Patients with LOPD showed improved hepatomegaly and liver transaminase level after ERT. Conclusion As ERT is effective for treatment of PD, early identification of this disease is very important. Thus, patients with IOPD should be considered candidates for clinical trials of new drugs in the future.

Kabuki syndrome (KS) is a rare genetic disease with a distinctive dysmorphic face, intellectual disability, and multiple congenital abnormalities. KS is inherited in an autosomal dominant manner. As the primary cause of KS, MLL2 mutations have been identified in 56-76% of affected individuals who have been tested, suggesting that there may be additional genes associated with KS. Recently, a few KS individuals have been found to have de novo partial or complete deletions of an X chromosome gene, KDM6A, which encodes a histone demethylase that interacts with MLL2. Nevertheless, mutations in MLL2 are the major cause of KS. Although there are a few reports of KS patients in Korea, none of these had been confirmed by genetic analysis. Here, we report a case of a Korean patient with clinical features of KS. Using direct sequencing, we identified a frameshift heterozygous mutation for MLL2: (c.5256_5257delGA;p.Lys1753Alafs*34). Clinically, the patient presented with typical facial features, and diagnosis of KS was based on the diagnostic criteria. While KS is a rare disease, other malformations that overlap with those found in individuals with KS are common. Hence, the diagnosis of KS by mutational analysis can be a valuable method for patients with KS-like syndromes. Furthermore, in the near future, other genes could be identified in patients with KS without a detectable MLL2 mutation.

PurposePrecocious 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.MethodsThe 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.ResultsThe 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

PurposeSingle-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.MethodsGenomic 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.ResultsEleven 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.ConclusionThe results of the present study showed that non-AC haplotypes of LIN28B had a significant association with PP in girls.

PurposeContinuous 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.MethodsA 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.ResultsThe 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.ConclusionThe 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.

Prader-Willi syndrome (PWS) is a complex multisystem genetic disorder characterized by hypothalamic-pituitary dysfunction. The main clinical features include neonatal hypotonia, distinctive facial features, overall developmental delay, and poor growth in infancy, followed by overeating with severe obesity, short stature, and hypogonadism later in development. This paper reviews recent updates regarding the genetic aspects of this disorder. Three mechanisms (paternal deletion, maternal disomy, and deficient imprinting) are recognized. Maternal disomy can arise because of 4 possible mechanisms: trisomy rescue (TR), gamete complementation (GC), monosomy rescue (MR), and postfertilization mitotic nondisjunction (Mit). Recently, TR/GC caused by nondisjunction at maternal meiosis 1 has been identified increasingly, as a result of advanced maternal childbearing age in Korea. We verified that the d3 allele increases the responsiveness of the growth hormone (GH) receptor to endogenous GH. This paper also provides an overview of endocrine dysfunctions in children with PWS, including GH deficiency, obesity, sexual development, hypothyroidism, and adrenal insufficiency, as well as the effects of GH treatment. GH treatment coupled with a strictly controlled diet during early childhood may help to reduce obesity, improve neurodevelopment, and increase muscle mass. A more active approach to correct these hormone deficiencies would benefit patients with PWS.

PurposeMucopolysaccharidosis 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.MethodsWe 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.ResultsPlasma 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).ConclusionThese results show that the mild phenotype may be related to residual lysosomal enzyme activity.

PurposeLong-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.MethodsWe 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.ResultsA 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

Kabuki syndrome (KS) is a rare genetic disease with a distinctive dysmorphic face, intellectual disability, and multiple congenital abnormalities. KS is inherited in an autosomal dominant manner. As the primary cause of KS, MLL2 mutations have been identified in 56-76% of affected individuals who have been tested, suggesting that there may be additional genes associated with KS. Recently, a few KS individuals have been found to have de novo partial or complete deletions of an X chromosome gene, KDM6A , which encodes a histone demethylase that interacts with MLL2 . Nevertheless, mutations in MLL2 are the major cause of KS. Although there are a few reports of KS patients in Korea, none of these had been confirmed by genetic analysis. Here, we report a case of a Korean patient with clinical features of KS. Using direct sequencing, we identified a frameshift heterozygous mutation for MLL2 : (c.5256_5257delGA;p.Lys1753Alafs"34). Clinically, the patient presented with typical facial features, and diagnosis of KS was based on the diagnostic criteria. While KS is a rare disease, other malformations that overlap with those found in individuals with KS are common. Hence, the diagnosis of KS by mutational analysis can be a valuable method for patients with KS-like syndromes. Furthermore, in the near future, other genes could be identified in patients with KS without a detectable MLL2 mutation. [ABSTRACT FROM AUTHOR]

PurposeMucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is rare lysosomal storage disorder caused by N-acetylgalactosamine-6-sulfatase (GALNS) deficiency. Only a few MPS IVA cases have been reported in the Korean literature; there is a paucity of research about clinical or radiologic findings for this disorder. Therefore, we studied clinical findings, radiological features, and genetic data of Korean MPS IVA patients for determining factors that may allow early diagnosis and that may thus improve the patients' quality of life.MethodMPS IVA was confirmed via assay for enzymatic activity of leukocytes in 10 patients. The GALNS gene was analyzed. Patients' charts were retrospectively reviewed for obtaining clinical features and evaluated for radiological skeletal surveys, echocardiography, pulmonary function test, and ophthalmologic test results.ResultNine patients had severe clinical phenotype, and 1 had an intermediate phenotype, on the basis of clinical phenotype criteria. Radiologic findings indicated skeletal abnormalities in all patients, especially in the hips and extremities. Eight patients had an odontoid hypoplasia, and 1 showed mild atlantoaxial subluxation and cord myelopathy. Genetic analysis indicated 10 different GALNS mutations. Two mutations, c.451C>A and c.1000C>T, account for 37.5% (6/16) and 25% (4/16) of all mutations in this samples, respectively.ConclusionAn understanding of the clinical and radiological features involved in MPS IVA may allow early diagnosis of MPS IVA. Adequate evaluations and therapy in the early stages may improve the quality of life of patients suffering from skeletal abnormalities and may reduce life-threatening effects of atlantoaxial subluxation.