한국인 Fragile-X 증후군 환자의 분자 유전학적 진단

김경모,유한욱 울산대학교 의과대학 1994 울산의대학술지 Vol.3 No.2

Fragile-X syndrome (FXS) is the most common cause of inherited mental retardation. Until recently, the diagnosis of FXS has been made based on the cytogenetic expression of the fragile site at Xq27.3 (FRAXA) in the patients' cultured cells and on the results of linkage analysis with DNA markers surrounding the fragile X locus. The recent cloning of fragile-X gene(FMR-1) made it possible investigate the molecular defects in FMR-1 gene of individuals at risk. Vast majority of molecular defects of FXS has been known to be an abnormally amplified trinucleotide(cytosine guanine guanine) repeat. This study aims at establishing the molecular genetic diagnosis of FXS as well as correlating genotype-phenotype analyzing the increment of amplified CGG repeat number, clinical findings, and cytogenetic expression rate in two Korean families with FXS patients. The FXS patients are tested cytogenetically & molecular genetically. The fragile site at Xq27.3 was cytogenetically expressed in folate deficient medium by culturing lymphocytes for 4 days. Molecular diagnostic approaches utilize the genomic DNA Southern blot analysis using genomic probe FXA 241 (ONCOR) and radiolabelled PCR-denaturing polyacrylamide gelelcetrophoresis. Each patient expressed a FRAXA site in folate deficient medium with the expression rate of 38%, 16% respectively. The molecular genetic study showed that each patient had the CGG amplification 1.6kb, 0.7-0.8kb in the FMR-1 gene respectively. In addition, this study clarified the carrier status of each family members. In conclusion, molecular genetic studies employed in this study can be utilized for a confimatory diagnostic purpose in FXS patients.

22q11.2 미세 결실 증후군 환아에서 내분비 기능 및 성장에 관한 연구

이종승,최진호,유한욱 대한소아내분비학회 2004 Annals of Pediatirc Endocrinology & Metabolism Vol.9 No.1

Performance Evaluation of Fiber-Optic Dosimeter According to Current-Time Product of Digital Radiography System

Yoo, Wook Jae,Jeon, Da Yeong,Seo, Jeong Ki,Shin, Sang Hun,Han, Ki Tek,Hong, Seung Han,Kim, Seon Guen,Sim, Hyeok In,Cho, Seung Hyun,Lee, Bong Soo Trans Tech Publications, Ltd. 2013 Advanced materials research Vol.718 No.-

<P>A fiber-optic dosimeter was developed using a plastic scintillating fiber, a plastic optical fiber, and a photomultiplier tube for measuring entrance surface dose over the low-energy range which is interested in diagnostic radiology. To evaluate the fabricated fiber-optic dosimeter, the scintillating light signals were measured by changing the current-time product whose values were determined by tube current and irradiation time of a digital radiography system. In conclusion, the trend of scintillating light signals of the fiber-optic dosimeter was similar with that of the entrance surface doses of a commercially available semiconductor dosimeter according to the current-time product.</P>

Clinical Features, Response to Treatment, Prognosis, and Molecular Characterization in Korean Patients with Inherited Urea Cycle Defects

Yoo, Han-Wook,Kim, Gu-Hwan,Seo, Eul-Ju The Korean Society of Inherited Metabolic Disease 2002 대한유전성대사질환학회지 Vol.2 No.1

The urea cycle, consisting of a series of six enzymatic reactions, plays key roles to prevent the accumulation of toxic nitrogenous compound and synthesize arginine de novo. Five well characterized diseases have been described, resulting from an enzymatic defect in the biosynthesis of one of the normally expressed enzyme. This presentation will focus on two representative diseases; ornithine transcarbamylase(OTC) deficiency and citrullinemia(argininosuccinate synthetase deficiency). OTC deficiency is one of the most common inborn error of urea cycle, which is inherited in X-linked manner. We identified 17 different mutations in 20 unrelated Korean patients with OTC deficiency; L9X, R26P, R26X, T44I, R92X, G100R, R141Q, G195R, M205T, H214Y, D249G, R277W, F281S, 853 del C, R320X, V323M and 10 bp del at nt. 796-805. These mutations occur at well conserved nucleotide sequences across species or CpG hot spot. The L9X and R26X lead to the disruption of leader sequences, required for directing mitochondrial localization of the OTC precursor. Their phenotypes are severe, and neonatal onset. The G100R, R277W and V323M mutations were uniquely identified in patients with late onset OTC deficiency. The other genotypes are associated with neonatal onset. Out of 20 patients with OTC deficiency, only 6 patients are alive; two were liver transplanted, and normal in growth and development at 2, 4 years after transplantation respectively. Citrullinemia is an autosomal recessive disease, caused by the mutations in the argininosuccinate synthetase(ASS) gene. We identified in 3 major mutations in 11 unrelated Korean patients with citrullinemia; G324S, $IVS6^{-2}$ A to G, and 67 bp ins at nt 1125-1126. Among these, the 67 base pair insertion mutation is novel. The allele frequency of each mutation is; G324S(45%), IVS6-2 A to G(32%), and 67 base pair insertion(14%). All patients are diagnosed at neonatal or infantile age. Interestingly, two patients presented with stroke like episode. Out of 11 patients, 5 patients died. Among 6 patients alive, one patient was successfully liver transplanted.

Development of orphan drugs for rare diseases

Yoo Han-Wook 대한소아청소년과학회 2024 Clinical and Experimental Pediatrics (CEP) Vol.67 No.7

Most rare diseases (orphan diseases) still lack approved treatment options despite major advances in research providing the necessary tools to understand their molecular basis and legislation providing regulatory and economic incentives to expedite the development of specific therapies. Addressing this translational gap is a multifaceted challenge, a key aspect of which is the selection of an optimal therapeutic modality to translate advances in rare disease knowledge to potential medicines known as orphan drugs. There are several strategies for developing orphan drugs for rare genetic disorders, including protein replacement therapies, small-molecule therapies (e.g., substrate reduction, chemical chaperone, cofactor, expression modification, and read-through therapies), monoclonal antibodies, antisense oligonucleotides, small interfering RNA or exon skipping therapies, gene replacement and direct genome-editing therapies, mRNA therapy, cell therapy, and drug repurposing. Each strategy has its own strengths and limitations in orphan drug development. Furthermore, numerous hurdles are present in clinical trials of rare genetic diseases because of difficulty with patient recruitment, unknown molecular physiology, the natural history of the disease, ethical concerns regarding pediatric patients, and regulatory challenges. To address these barriers, the rare genetic diseases community, including academic institutions, industry, patient advocacy groups, foundations, payers, and government regulatory and research organizations, must become engaged in discussions about these issues.

Ligand-Dependent Interaction of PPARδ With T-Cell Protein Tyrosine Phosphatase 45 Enhances Insulin Signaling

Yoo, Taesik,Ham, Sun Ah,Lee, Won Jin,Hwang, Seon In,Park, Jin-A,Hwang, Jung Seok,Hur, Jinwoo,Shin, Ho-Chul,Han, Sung Gu,Lee, Chi-Ho,Han, Dong Wook,Paek, Kyung Shin,Seo, Han Geuk American Diabetes Association 2018 Diabetes Vol.67 No.3

<P>Peroxisome proliferator-activated receptor (PPAR) delta plays a pivotal role in metabolic homeostasis through its effect on insulin signaling. Although diverse genomic actions of PPAR delta are postulated, the specific molecular mechanisms whereby PPARd controls insulin signaling have not been fully elucidated. We demonstrate here that short-term activation of PPAR delta results in the formation of a stable complex with nuclear T-cell protein tyrosine phosphatase 45 (TCPTP45) isoform. This interaction of PPAR delta with TCPTP45 blocked translocation of TCPTP45 into the cytoplasm, thereby preventing its interaction with the insulin receptor, which inhibits insulin signaling. Interaction of PPAR delta with TCPTP45 blunted interleukin 6-induced insulin resistance, leading to retention of TCPTP45 in the nucleus, thereby facilitating deactivation of the signal transducer and activator of transcription 3 (STAT3)-suppressor of cytokine signaling 3 (SOCS3) signal. Finally, GW501516-activated PPAR delta improved insulin signaling and glucose intolerance in mice fed a high-fat diet through its interaction with TCPTP45. This novel interaction of PPAR delta constitutes the most upstream component identified of the mechanism downregulating insulin signaling.</P>

Molecular characterization and prenatal molecular evaluation of three fetuses in four unrelated Korean families with Lesch-Nyhan syndrome

Yoo, Han-Wook,Kim, Gu-Hwan Korean Society of Medical Genetics 1998 대한의학유전학회지 Vol.2 No.1

The Lesch-Nyhan syndrome which is caused by the deficiency of hypoxanthine guanine phosphoribosyltransferase is an X-linked recessive disorder characterized by hyperuricemia, choreoathetosis, mental retardation and compulsive self-injurious behavior. Clinical management of the patients with the Lesch-Nyhan syndrome is frustrating and requires burdensome medical treatment since it cripples the patient and shortens the life span by progression of neurological symptoms, but there are no cures or measures for relieving relentless natural course of the disease yet. Therefore, prenatal diagnosis of the affected fetus is important in genetic counselling for the family at high risk. In this study, four different mutations in the HPRT gene of four probands have been identified in four unrelated families; K215X, Q109X, nt.631 ${\Delta}A$, and nt.289 ${\Delta}GT$. Two mutations among them altered restriction enzyme sites; SpeI for Q109X and MaeI for nt.289 ${\Delta}GT$. Based on their molecular defects, prenatal diagnoses of 3 the fetuses were successfully made between ninth and eleventh week of gestation by polymerase chain reaction (PCR), restriction digestion and DNA sequencing using cDNA obtained from chorionic villus samples (CVS). We predicted the outcome of all fetuses prenatally. Among the three fetuses two were male and one was female according to the identification made by PCR amplification of the sex determining region of the Y chromosome(SRY) gene. Each carried a wild type allele for the corresponding mutant allele. They were also tested postnatally for the mutations to be unaffected.

Mutation analyses in Korean patients with MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes)

Yoo, Han-Wook,Kim, Gu-Hwan,Ko, Tae-Sung Korean Society of Medical Genetics 1997 대한의학유전학회지 Vol.1 No.1

The mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is inherited maternally, in which the MTTL1*MELAS 3243 mutation has been most commonly found as a heteroplasmy of A to G point mutation in the $tRNA^{Leu(UUR)}$ gene. The MTTL1*MELAS 3271 mutation is known to be the second common mutation, though clinical features of both mutations are not remarkably different. Recently, a variety of minor mutations have been reported in patients with MELAS. In this study, major efforts have been made to investigate the allele frequency of major three mutations including MTTL1*MELAS 3243, 3252, 3271 in 10 Korean families with MELAS probands. The PCR and subsequent direct sequencing of the PCR product in the regions spanning these three mutation sites were employed to identify the mutation in each proband. All family members have been screened for the presence of these three mutations by PCR-RFLP assay using Apa I, Acc I and Bfr I restriction enzymes. The MTTL1*MELAS 3243 mutation was most commonly found (7 out of 10 families tested) followed by the MTTL1*MELAS 3271 which was identified in 1 out of 10 families. In the remaining 2 families none of three mutations were found, indicating the presence of either nuclear mutation or yet unidentified mitochondrial DNA mutation in these families.

Mutation analyses in Korean patients with MELAS(mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes)

Han-Wook Yoo,Gu-Hwan Kim,Tae-Sung Ko 대한의학유전학회 1997 대한의학유전학회지 Vol.1 No.1

The mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is inherited maternally, in which the MTTL1*MELAS 3243 mutation has been most, commonly found as a heteroplasmy of A to G point mutation in the tRNALeu(UUR) gene. The MTTL1*MELAS 3271 mutation is known to be the second common mutation, though clinical features of both mutations are not remarkably different. Recently, a variety of minor mutations have been reported in patients with MELAS. In this study, major efforts have been made to investigate the allele frequency of major three mutations including MTTL1*MELAS 3243, 3252, 3271 in 10 Korean families with MELAS probands. The PCR end subsequent direct sequencing of the PCR product in the regions spanning these three mutation sites were employed to identify the mutation in each proband. All family members have been screened for the presence of these three mutations by PCR-RFLP assay using Apa Ⅰ, Ace Ⅰ and Bfr Ⅰ restriction enzymes. The MTTL1*MELAS 3243 mutation was most commonly found (7 out of 10 families tested) followed by the MTTL1*MELAS 3271 which was identified in 1 out of 10 families. In the remaining 2 families, none of three mutations were found, indicating the presence of a either nuclear mutation or yet unidentified mitochondrial DNA mutation in these families.

Molecular characterization and prenatal molecular evaluation of three fetuses in four unrelated Korean families with Lesch-Nyhan syndrome

Han-Wook Yoo,Gu-Hwan Kim 대한의학유전학회 1998 대한의학유전학회지 Vol.2 No.1

The Lesch-Nyhan syndrome which is caused by the deficiency of hypoxanthine guanine phosphoribosyl-transferase is an X-linked recessive disorder characterized by hyperuricemia, choreoathetosis, mental retardation and compulsive self-injurious behavior. Clinical management of the patients with the Lesch-Nyhan syndrome is frustrating and requires burdensome medical treatment since it cripples the patient and shortens the life span by progression of neurological symptoms, but there are no cures or measures for relieving relentless natural course of the disease yet. Therefore, prenatal diagnosis of the affected fetus is important in genetic counselling for the family at high risk. In this study, four different mutations in the HPRT gene of four probands have been identified in four unrelated families; K215X, Q109X, nt.631 ΔA, and nt.289 ΔGT. Two mutations among them altered restriction enzyme sites; Spel for Q109X and Mael for nt.289 ΔGT. Based on their molecular defects, prenatal diagnoses of 3 the fetuses were successfully made between ninth and eleventh week of gestation by polymerase chain reaction (PCR), restriction digestion and DNA sequencing using cDNA obtained from chorionic villus samples (CVS). We predicted the outcome of all fetuses prenatally. Among the three fetuses two were male and one was female according to the identification made by PCR amplification of the sex determining region of the Y chromosome (SRY) gene. Each carried a wild type allele for the corresponding mutant allele. They were also tested postnatally for the mutations to be unaffected.