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Biomedical subjects

Jong-Won Kim

Publications and source records attributed to Jong-Won Kim.

At least 19 recordsLinked to original sources

Identification of a novel mutation in a Korean patient with oculopharyngeal muscular dystrophy.

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset muscle disorder characterized by progressive dysphagia and bilateral ptosis. Mutations in the polyadenylate binding protein nuclear 1 (PABPN1) gene have been found to cause OPMD. The typical mutation is a stable trinucleotide repeat expansion in the first exon of the PABPN1 gene, in which (GCG)(6) is the normal repeat length. We investigated a Korean patient with OPMD and identified a novel mutation: a heterozygous insertion of a 9-bp sequence [(GCG)(GCA)(GCA); c.27_28insGCGGCAGCA] instead of the (GCG) repeat expansion, resulting in an in-frame insertion of three alanines (p.A10insAAA). To the best of our knowledge, this is the first report of a genetically confirmed case of OPMD in Korea.

Blepharoptosis↗

Heterozygosities of 735 microsatellite markers and background linkage disequilibrium in the Korean population.

Suitability of a specific population for linkage disequilibrium mapping studies of complex traits may be assessed by investigating the background linkage disequilibrium (BLD). We are unaware of studies for quantifying the degree of BLD in the Korean population, although the population may be a good candidate for mapping of complex trait genes through whole-genome association studies. It is useful to investigate the properties of genetic isolates in East Asia and to compare them to genetic isolates in Europe. We analyzed the extent of BLD in the Korean population using 735 microsatellite markers and compared the results with the Icelander population, which is one of the European expanded genetic isolates. The Korean population exhibited a level of BLD comparable with the Icelander population. The inference of population structure using the model with admixture showed that each individual has allele copies originating from K populations in equal proportions. Therefore, we believe that factors other than genetic distance, such as recent admixture, have not contributed to the level of BLD. Our results showed that the Korean population, which is an expanded population with no evidence of admixture, has a BLD level comparable with the Icelander population. Therefore, the Korean population can be used for fine mapping of either complex traits or monogenic diseases.

Adult↗

Monoamine transporter gene polymorphisms and antidepressant response in koreans with late-life depression.

CONTEXT: Polymorphisms in the serotonin transporter gene (5-HTT) may influence antidepressant response to selective serotonin reuptake inhibitors (SSRIs). The norepinephrine transporter (NET) is the analogous target for norepinephrine reuptake inhibitors (NRIs). OBJECTIVE: To determine whether antidepressant responses to SSRIs or NRIs are associated with genetic polymorphisms of the corresponding monoamine transporters. DESIGN, SETTING, AND PATIENTS: A 6-week naturalistic treatment study with blinded outcome evaluation of 241 Korean inpatients and outpatients with major depression at an academic psychiatry service. Patients were recruited to the study from March 1998 through February 2003. INTERVENTIONS: Treatment with an SSRI (fluoxetine or sertraline; n = 136) or an NRI (nortriptyline; n = 105) antidepressant. Adherence was assessed by measuring plasma concentration at 4 weeks. Patients were genotyped for s/l polymorphisms in 5-HTT promoter region (5-HTTLPR), 5-HTT intron 2 s/l variation, and NET G1287A variation of exon 9. MAIN OUTCOME MEASURES: An SSRI and NRI response (defined as > or =50% decrease in Hamilton Rating Scale for Depression score at 6 weeks). RESULTS: NRI response was associated with the NET G1287A polymorphism (odds ratio [OR], 7.54; 95% confidence interval [CI], 2.53-22.49; P<.001). An SSRI response was associated with the 5-HTT intron 2 s/l variation (OR, 20.11; 95% CI, 4.27-94.74; P<.001). The 5-HTTLPR was also associated with an SSRI response (OR, 3.34; 95% CI, 1.41-7.91; P = .006). In contrast to studies in white patients, the favorable allele for SSRI response was S 5-HTTLPR. The S 5-HTTLPR was associated also with NRI response (OR, 3.73; 95% CI, 1.32-10.53; P = .01). The NET polymorphism was not associated with an SSRI response. The NET G1287A GG genotype (56% of the population) was associated with better response to the NRI (83.3% [35/42]) than to SSRI (58.7% [44/75]) (OR, 3.52; 95% CI, 1.39-8.95; P = .006). Some genotype combinations were associated with high rates of antidepressant response and others with low rates of response. CONCLUSIONS: Monoamine transporter gene polymorphisms were associated with response to antidepressants with homologous monoamine transporter targets. Combinations of polymorphisms were informative for response and nonresponse. Confirmation of these preliminary findings would permit refined pharmacogenetic selection of antidepressant treatment.

Adult↗

Characterization of late-onset citrullinemia 1 in a Korean patient: confirmation by argininosuccinate synthetase gene mutation analysis.

A 16-month old boy was referred to our hospital for evaluation of recurrent generalized tonic clonic seizures. Metabolic evaluation revealed significant hyperammonemia (1,112 microg/dl). Amino acid/acylcarnitine screening using tandem mass spectrometry showed markedly increased plasma levels of citrulline (1,350 microM/l) with undetectable levels of arginine and arginosuccinic acid. Urinary excretion of citrulline was markedly increased (38,617 microM/g creatinine). Brain MRI findings showed diffuse high-signal intensity lesions, that involved gray and white matter in both frontal lobes and insula with edematous changes; these findings were consistent with the acute stage of citrullinemia (CTLN). Mutation analysis of the argininosuccinate synthetase (ASS) gene, in this patient, showed a Gly324Ser mutation in exon 13, and a 67-bp duplication mutation in exon 15 (c.1128-6_1188dup67). The patient was confirmed as having late-onset CTLN1 and treated with anticonvulsants, lactulose enema, protein restricted diet and arginine. Here we describe a case of late-onset CTLN1 in a patient by biochemical analyses and ASS gene mutation confirmation. This is the first report of a Korean patient with late-onset CTLN1 confirmed by ASS gene mutation identification.

Argininosuccinate Synthase↗

Pharmacokinetic parameters of bromperidol in Korean subjects.

We have presented pharmacokinetic parameters of bromperidol (BP) in 14 healthy Korean subjects. Additionally, we have investigated the effects of dose and genetic polymorphisms on BP metabolism and on extrapyramidal symptoms (EPS). The T(max) (3.9 +/- 0.9 h), clearance (1.37 +/- 0.52 ml/h/kg), and t(1/2) (20.4 +/- 3.7 h) obtained in our study are comparable to those in previous Caucasian studies, although pharmacokinetic profiles were affected by the BP dose. We could not prove any significant correlations between BP metabolism or adverse effects and genetic factors because the number of subjects was small. Further studies with a larger population are needed to determine the influence of genetic factors on BP therapy.

Adult↗

Novel mutations of RET gene in Korean patients with sporadic Hirschsprung's disease.

BACKGROUND/PURPOSE: Hirschsprung's disease (HSCR) is a congenital abnormality that can cause an intestinal obstruction. Although HSCR demonstrates a sex-modified polygenic inheritance with contributions from multiple genes, mutations in the RET gene are believed to be the major sign of susceptibility in the development of disease. The allele frequency of polymorphisms was mostly tested in the American and European population, but the data of an ethnically diverse nonwhite population are unclear. METHODS: All 21 exons and intron/exon boundaries of the RET gene in 18 Korean patients with sporadic HSCR and 84 normal individuals were screened using polymerase chain reaction amplification and direct sequencing. RESULTS: A total of 11 different nucleotide substitutions were identified. Of these, 2 were new missense mutations (C558Y, cysteine-rich domain; R844W, tyrosine kinase domain) and 9 previously described variants. This study also analyzed the haplotypes for the association between the variants identified with HSCR, but the estimated RET haplotypes did not show any disease risk. CONCLUSIONS: This study identified additional mutations of RET gene, which represents the first comprehensive genetic dissection of sporadic HSCR disease in Koreans.

Asian People↗

New variations of the EDNRB gene and its association with sporadic Hirschsprung's disease in Korea.

BACKGROUND/PURPOSE: The endothelin receptor B (EDNRB) signaling pathway, which is the second major susceptible gene for Hirschsprung's disease (HSCR), is crucial for the development of the enteric nervous system. The allele frequency of polymorphisms was mostly tested in the American and European population, but the data of an ethnically diverse, non-Caucasian population are unclear. To further investigate the variants and haplotypes of the EDNRB gene, this study examined sequence variations in Korean patients with sporadic HSCR. METHODS: All 8 exons and intron/exon boundaries of the EDNRB gene in 18 Korean patients with sporadic HSCR and 84 healthy individuals were screened using PCR amplification and direct sequencing. RESULTS: A total of 8 different nucleotide substitutions were identified. Of these, 4 were new variants (promoter-116C>T; 5'UTR-121G>T; IVS4+62C>A; IVS5+121G>C) and the others were previously described variants. The distribution of variations was even different from that reported for Chinese and Japanese subjects as well as other ethnic groups. This study also analyzed the haplotypes for an association between the variants identified with HSCR. CONCLUSIONS: This study identified additional sequence variants of the EDNRB gene, but the estimated EDNRB haplotypes did not show any disease risk.

Asian People↗

Synchronization in complex networks with a modular structure.

Networks with a community (or modular) structure arise in social and biological sciences. In such a network individuals tend to form local communities, each having dense internal connections. The linkage among the communities is, however, much more sparse. The dynamics on modular networks, for instance synchronization, may be of great social or biological interest. (Here by synchronization we mean some synchronous behavior among the nodes in the network, not, for example, partially synchronous behavior in the network or the synchronizability of the network with some external dynamics.) By using a recent theoretical framework, the master-stability approach originally introduced by Pecora and Carroll in the context of synchronization in coupled nonlinear oscillators, we address synchronization in complex modular networks. We use a prototype model and develop scaling relations for the network synchronizability with respect to variations of some key network structural parameters. Our results indicate that random, long-range links among distant modules is the key to synchronization. As an application we suggest a viable strategy to achieve synchronous behavior in social networks.

Action Potentials↗

Lack of a genetic association between the CTLA-4 gene and Graves' disease in Koreans.

Graves' disease (GD) is a complex autoimmune thyroid disease with a strong genetic component. The cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) gene, which encodes a negative regulator of the T-lymphocyte immune response, has been reported to be associated and/or linked to GD. Therefore, in order to determine the contribution of CTLA-4 in GD in Koreans, we genotyped the five single nucleotide Polymorphisms (SNPs) of the CTLA-4 gene, including +49, CT60, JO31, JO30, and JO27-1 in Korean spatients with GD and healthy controls. Two hundred seventy-eight Korean patients with GD from the Thyroid Clinic and 472 healthy controls from the Health Screening Center of Samsung Medical Center were enrolled in this study. The +49A/G polymorphism of the CTLA-4 gene exon 1 was sequenced directly and the genotyping of the remaining 4 SNPs was accomplished using a Snapshot. In addition, the association of haplotypes with a combination of the above markers was also examined in 278 Korean patients with GD and 472 controls. The results showed that there was no significant positive association between any individual SNP or haplotype comprising of the four 3 untranslated region (UTR) SNPs (CT60, JO31, JO30, and JO27-1) and GD. These data provide little support for CTLA-4 to play a role in the genetic predisposition to GD in Koreans. However, it will be necessary to validate or replicate this association in other independent large-size ethnic groups.

3' Untranslated Regions↗

Sequence-based CYP2D6 genotyping in the Korean population.

For clinical application of pharmacogenetic tests, quantitative prediction of enzyme activity based on accurate determination of genotype is essential. There has been limited information available on the genetic polymorphism of CYP2D6 in the Korean population. In this study, CYP2D6 genotypes were assessed in 400 Korean subjects. Twenty-eight different CYP2D6 alleles and 35 genotypes were detected. On the basis of the genotype determined, the frequency of poor metabolizers and ultrarapid metabolizers were 0.22% and 1.25%, respectively. The CYP2D6 activity expected in regard to different allele combinations varies widely within the extensive and intermediate metabolizer groups. The frequencies of CYP2D6*10 and CYP2D6*5 were 45.00% and 6.13%, respectively. CYP2D6*10xN was found in 4 out of 9 cases with a CYP2D6 duplication. Fifteen heterozygotes for *41 were noted. In addition, the authors measured plasma concentrations of 16 healthy volunteers after administration of nortriptyline and identified the impact of the CYP2D6 genotype on nortriptyline metabolism. This is the first large-scale study to examine the genetic polymorphism of CYP2D6 using sequence-based genotyping in an Asian population. Our results further the understanding of CYP2D6 pharmacogenetics and could be helpful for future clinical studies in the Asian population.

Adult↗

A novel mutation W252X in the WAS gene in a Korean patient with Wiskott-Aldrich syndrome.

Wiskott-Aldrich syndrome (WAS) is a primary immunodeficiency disorder characterized by recurrent infection, eczema, and microthrombocytopenia. WAS is inherited in an X-linked recessive pattern, and various mutations in the WAS gene on the X chromosome are the genetic basis of WAS. A 7-month-old Korean boy presented with recurrent bloody diarrhea, eczema, and persistent thrombocytopenia with small platelets. Direct sequence analysis of the entire coding region of the WAS gene showed a novel nonsense mutation with a G-to-A substitution at the nucleotide position 756 on exon 8, leading to a premature termination at codon 252 (c.756G>A; p.W252X). Family study revealed that neither of the parents had the mutation, indicating the de novo occurrence of the mutation.

Asian People↗

Report of a Korean patient with cystic fibrosis, carrying Q98R and Q220X mutations in the CFTR gene.

Although cystic fibrosis (CF) is one of the most frequently seen autosomal-recessive disorders in Caucasians, it is extremely rare in the Korean population. Recently, a 15-yr-old Korean boy was admitted to our hospital complaining of coughing, sputum, and exertional dyspnea. Chest radiographs and computed tomographic chest and paranasal sinus scans revealed diffuse bronchiectasis and pansinusitis. Pulmonary function tests revealed severe obstructive impairment. The average sweat chloride concentrations on both of the patients' forearms were 63.0 mM/L (reference limit: < 40 mM/L). Upon mutation analysis, two different mutations (Q98R and Q220X) were identified in the cystic fibrosis transmembrane conductance regulator gene, both of which had been previously detected in CF patients, one from France and the other from England. As CF is quite rare in Korea, the diagnosis of CF in this patient might be delayed. Therefore, we recommend that a diagnosis of CF should be suspected in patients exhibiting unexplained chronic respiratory symptoms.

Adolescent↗

Clinical and genetic analysis of Korean patients with Miyoshi myopathy: identification of three novel mutations in the DYSF gene.

Miyoshi myopathy (MM) is an autosomal recessive distal muscular dystrophy caused by mutations in the dysferlin gene (DYSF) on chromosome 2p13. Although MM patients and their mutations in the DYSF gene have been found from all over the world, there is only one report of genetically confirmed case of MM in Korea. Recently, we encountered three unrelated Korean patients with MM and two of them have previously been considered as having a type of inflammatory myopathy. The clinical and laboratory evaluation showed typical features of muscle involvement in MM in all patients but one patient initially had moderate proximal muscle involvement and another showed incomplete quadriparesis with rapid progression. Direct sequencing analysis of the DYSF gene revealed that each patient had compound heterozygous mutations (Gln832X and Trp992Arg, Gln832X and Trp999Cys, and Lys1103X and Ile1401HisfsX8, respectively) among which three were novel. Although MM has been thought to be quite rare in Korea, it should be considered in a differential diagnosis of patients exhibiting distal myopathy.

Adult↗

X-linked Opitz G/BBB syndrome: identification of a novel mutation and prenatal diagnosis in a Korean family.

X-linked Opitz G/BBB syndrome (XLOS; MIM 300000) is a rare multiple congenital anomaly disorder that is characterized by facial anomalies, laryngeal/tracheal/esophageal defects and genitourinary abnormalities. XLOS is caused by mutations in the MID1 gene which encodes a microtubule-associated RING-Bbox-Coiled-coil (RBCC) protein. We recently found a four-year Korean male patient who was suspected of having XLOS. Mutation analysis of the MID1 gene in the patient and his mother demonstrated that the patient had a novel insertion mutation (c.1798_1799-insC), and his mother was a heterozygous carrier of the mutation. After identification of the causative mutation in this family, prenatal diagnosis of two consecutive fetuses were successfully undertaken. This is the first report on a genetically confirmed case of XLOS in Korea.

Abnormalities, Multiple↗

A case of intolerance to warfarin dosing in an intermediate metabolizer of CYP2C9.

We report a case of intolerance to warfarin dosing due to impaired drug metabolism in a patient heterozygous for the CYP2C9*3 allele. A 30-year-old woman with an artificial cardiac pacemaker was taking warfarin to prevent thromboembolism. This patient had an extremely elevated international normalized ratio (INR) of prothrombin time (PT) following standard doses of warfarin and experienced difficulties during the induction of anticoagulation. Genotyping for CYP2C9 revealed that this patient was an intermediate metabolizer with genotype CYP2C9*1/*3. This case suggests the clinical usefulness of pharmacogenetic testing for individualized dosage adjustments of warfarin.

Adult↗

Mutation analysis of the GNE gene in Korean patients with distal myopathy with rimmed vacuoles.

Distal myopathy with rimmed vacuoles (DMRV; MIM 605820) is an autosomal recessive neuromuscular disorder characterized by weakness of the anterior compartment of the lower limbs, sparing the quadriceps muscles. Recently, mutations in the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) gene have been identified as the genetic basis of DMRV. To investigate the mutation spectrum of the GNE gene in Korean patients with DMRV, we performed clinical and genetic analysis of nine unrelated patients suspected to have DMRV. Direct sequencing analysis revealed that eight out of nine patients (88.9%) were either homozygous or compound heterozygous for GNE gene mutations, including three known (C13S, R129Q, and V572L) and two novel mutations (M29T and A591T) [corrected] The allelic frequencies of the V572L and C13S mutations were 68.8% (11/16) and 12.5% (2/16), respectively. These results suggest that screening for GNE gene mutations in patients suspected to have DMRV would be helpful for molecular diagnosis of DMRV in the Korean population.

Base Sequence↗

TP53BP2 locus is associated with gastric cancer susceptibility.

We investigated the association of the TP53BP2 locus with gastric cancer susceptibility in a Korean population. We assayed 9 single nucleotide polymorphisms (SNP) in an 82.5 kb region that included the TP53BP2 locus in 233 male gastric cancer patients and 390 unaffected healthy male controls. The allelic frequencies of 4 SNP within TP53BP2, g.206692C>T, g.198267A>T, g.164895G>A and g.152389A>T, differed significantly between cases and controls (p < or = 0.0376). When compared to carriers of non-risk alleles, individuals homozygotic for each of the risk alleles had a 50% increase in risk of gastric cancer (age-adjusted odds ratio [OR] > or = 1.48; p < or = 0.0371). Furthermore, these 4 significantly associated SNP were in strong linkage disequilibrium (r2 > or = 0.51). Haplotype analysis showed that individuals with the CAGA haplotype, consisting of the risk alleles at each SNP, had a 1.55-fold higher risk for gastric cancer than individuals with the haplotype TTAT, consisting of the non-risk alleles at each SNP (OR = 1.55; 95% confidence interval [CI] = 1.13-2.14; p = 0.00705). Two other SNP were not polymorphic in the study subjects, whereas the other 3 SNP, located toward the outside of the TP53BP2 locus, were not associated with gastric cancer susceptibility. Although the location of the pathogenic variant is not yet known, our results suggest that the TP53BP2 locus is associated with susceptibility to gastric cancer in the Korean population.

Adult↗