• Journal of Genetic Medicine
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• 제18권2호
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• pp.147-151
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• 2021

The Say-Barber-Biesecker-Young-Simpson variant of Ohdo syndrome (SBBYSS) (Online Mendelian Inheritance in Man #603736) is a rare autosomal dominant disorder and clinically features blepharophimosis with ptosis, a mask-like facial appearance, cryptorchidism, congenital heart defect, long thumbs/great toes, and thyroid dysfunction. The etiology of SBBYSS has been shown to be due to heterozygous KAT6B gene mutation. Here we report a case of a neonate with SBBYSS identified a novel mutation in KAT6B gene. The patient showed typical dysmorphic facies, cryptorchidism with micropenis, overriding fingers, and long thumbs and toes at birth. He had also hypothyroidism, large atrial septal defect, and sensorineural hearing loss. The next generation sequencing identified a heterozygous novel variant, c.5206C>T (p.Gln1736Ter) in KAT6B gene. At the 9 months of age, he underwent patch closure for atrial septal defect. Until the 12-month follow-up, he was under-developed.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권1호
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• pp.37-40
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• 2014

Purpose: Crigler-Najjar syndrome type II (CN-2) is characterized by moderate non-hemolytic unconjugated hyperbilirubinemia as a result of severe deficiency of bilirubin uridine diphosphate-glucuronosyltransferase (UGT1A1). The study investigated the mutation spectrum of UGT1A1 gene in Korean children with CN-2. Methods: Five Korean CN-2 patients from five unrelated families and 50 healthy controls were enrolled. All five exons and flanking introns of the UGT1A1 gene were amplified by polymerase chain reaction (PCR) and the PCR products were directly sequenced. Results: All children initially presented with neonatal jaundice and had persistent indirect hyperbilirubinemia. Homozygous p.Y486D was identified in all five patients. Three patients had an associated homozygous p.G71R and two a heterozygous p.G71R. The allele frequency of p.Y486D and p.G71R in healthy controls was 0 and 0.16, respectively. No significant difference in mean serum bilirubin levels was found between homozygous carriers of p.G71R and heterozygous carriers. Conclusion: The combination of homozygous p.Y486D and homozygous or heterozygous p.G71R is identified. The p.Y486D and p.G71R can be screened for the mutation analysis of UGT1A1 in Korean CN-2 patients.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제2권2호
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• pp.164-168
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• 1999

Background: Wilson disease (WD) is an autosomal recessive disorder of copper transport and characterized by degenerative changes in the brain, liver dysfunction, and Kayser-Fleischer rings due to toxic accumulation of copper. Since the identification of Wilson disease gene (ATP7B), more than 80 mutations have been detected among the different ethnic groups. Methods: Twenty three children with Wilson disease were included in this study. They were all diagnosed by low serum ceruloplasmin and increased 24 hour urinary copper excretion with characteristic clinical findings. We analysed WD gene mutation by assessing the nucleotide sequence of exon 7, 8, 9 and 10 including intron-exon boundaries of ATP7B gene from genomic DNA. Results: Arg778Leu mutation was identified in 16 WD patients; three were homozygous and 13 were heterozygous for this mutation. Of the 46 alleles, 19 alleles had a Arg778Leu mutation (19/46=41%). Homozygote patients had neurologic forms of WD. Arg778Leu mutation was not found among 50 normal healthy persons. Conclusion: Arg778Leu mutation is a common mutation in Korean WD gene. Arg778Leu mutation screening might be used as a useful supplementary diagnostic test in some patients to confirm Wilson disease in Korea.

• Annals of Clinical Neurophysiology
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• 제21권1호
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• pp.57-60
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• 2019

Axonal Charcot-Marie-Tooth disease (CMT2) has most frequently been associated with mutations in the MFN2 gene. MFN2 encodes mitofusin 2, which is a mitochondrial fusion protein that plays an essential role in mitochondrial function. We report CMT2 in a Korean father and his son that manifested with gait difficulties and progressive atrophy of the lower legs. Molecular analysis revealed a novel heterozygous c.2096T>C (p.Leu699Pro) mutation in the exon 18 of MFN2 in both subjects. We suggest that this novel mutation in MFN2 is probably a pathogenic mutation for CMT2.

• 한국환경성돌연변이발암원학회지
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• 제19권1호
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• pp.7-13
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• 1999

The mouse lymphoma thymidine kinase (tk+/-) gene assay (MOLY) using L5178Y tk+/- mouse lymphoma cell line is one of the mammalian forward mutation assays. It is well known that MOLY has many advantages and more sensitive than the other mammalian forward mutation assays such as x-linked hyposanthine phosphoribosyltransferase (hprt) gene assay. The target gene of MOLY is a heterozygous tk+/- gene located in 11 chromosome of L5178Y tk+/- cell, so it is able to detect the wide range of genetic changes like point mutation, deletion, rearrangement, and mitotic recombination within tk gene or deletion of entire chromosome 11. MOLY has relatively short expression time (2-3 days) compared to 1 week of hprt gene assay. MOLY can also induce relatively high mutant frequency so a large number of events can be recorded. The bimodal distribution of colony size which may indicate gene mutation and chromosome breakage potential of chemicals according to mutation scale such as large normal-growing mutants and small slow-growing mutants can be observed in this assay. The statistical analysis of data can be performed using the MUTANT program developed by York Electronic Research in association with Hazelton as recommended by the UKEMS (United Kingdom Environmental Mutagen Society) guidelines. This report reviewed MOLY using the microtiter cloning technique (microwell assay).

• 대한약학회:학술대회논문집
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• 대한약학회 2005년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.104-105
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• 2005

• Genomics & Informatics
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• 제20권2호
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• pp.24.1-24.8
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• 2022

Hypomyelinating leukodystrophy type 2 (HLD2), is an inherited genetic disease of the central nervous system caused by recessive mutations in the gap junction protein gamma 2 (GJC2/GJA12). HLD2 is characterized by nystagmus, developmental delay, motor impairments, ataxia, severe speech problem, and hypomyelination in the brain. The GJC2 sequence encodes connexin 47 protein (Cx47). Connexins are a group of membrane proteins that oligomerize to construct gap junctions protein. In the present study, a novel missense mutation gene c.760G>A (p.Val254Met) was identified in a patient with HLD2 by performing whole exome sequencing. Following the discovery of the new mutation in the proband, we used Sanger sequencing to analyze his affected sibling and parents. Sanger sequencing verified homozygosity of the mutation in the proband and his affected sibling. The autosomal recessive inheritance pattern was confirmed since Sanger sequencing revealed both healthy parents were heterozygous for the mutation. PolyPhen2, SIFT, PROVEAN, and CADD were used to evaluate the function prediction scores of detected mutations. Cx47 is essential for oligodendrocyte function, including adequate myelination and myelin maintenance in humans. Novel mutation p.Val254Met is located in the second extracellular domain of Cx47, both extracellular loops are highly conserved and probably induce intramolecular disulfide interactions. This novel mutation in the Cx47 gene causes oligodendrocyte dysfunction and HLD2 disorder.

• Molecules and Cells
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• 제38권3호
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• pp.251-258
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• 2015

Germline mutations in the breast cancer type 2 susceptibility gene (BRCA2) are linked to familial breast cancer and the progressive bone marrow failure syndrome Fanconi anaemia. Established Brca2 mouse knockout models show embryonic lethality, but those with a truncating mutation at the C-terminus survive to birth and develop thymic lymphoma at an early age. To overcome early lethality and investigate the function of BRCA2, we used T cell-specific conditional Brca2 knockout mice, which were previously shown to develop thymic lymphoma at a low penetrance. In the current study we showed that the number of peripheral T cells, particularly na$\ddot{i}$ve pools, drastically declined with age. This decline was primarily ascribed to improper peripheral maintenance. Furthermore, heterozygous mice with one wild-type Brca2 allele manifested reduced T cell numbers, suggesting that Brca2 haploinsufficiency might also result in T cell loss. Our study reveals molecular events occurring in Brca2-deficient T cells and suggests that both heterozygous and homozygous Brca2 mutation may lead to dysfunction in T cell populations.

• Clinical and Experimental Pediatrics
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• 제54권11호
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• pp.470-472
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• 2011

Familial hyperkalemic periodic paralysis (HYPP) is an autosomal-dominant channelopathy characterized by transient and recurrent episodes of paralysis with concomitant hyperkalemia. Mutations in the skeletal muscle voltage-gated sodium channel gene $SCN4A$ have been reported to be responsible for this disease. Here, we report the case of a 16-year-old girl with HYPP whose mutational analysis revealed a heterozygous c.2111C>T substitution in the $SCN4A$ gene leading to a Thr704Met mutation in the protein sequence. The parents were clinically unaffected and did not have a mutation in the $SCN4A$ gene. A $de$ $novo$ $SCN4A$ mutation for familial HYPP has not previously been reported. The patient did not respond to acetazolamide, but showed a marked improvement in paralytic symptoms upon treatment with hydrochlorothiazide. The findings in this case indicate that a $de$ $novo$ mutation needs to be considered when an isolated family member is found to have a HYPP phenotype.

• Clinical and Experimental Pediatrics
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• 제57권2호
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• pp.91-95
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• 2014

Griscelli syndrome type 2 (GS2) is a rare autosomal recessive disease caused by mutations in the RAB27A gene. It is characterized by cutaneous hypopigmentation, immunodeficiency, and hemophagocytic lymphohistiocytosis. We describe 2 brothers who had GS2 with clinically diverse manifestations. The elder brother presented with a purely neurological picture, whereas the younger one presented with fever, pancytopenia, hepatosplenomegaly, and erythema nodosum. Considering that cutaneous hypopigmentation was a common feature between the brothers, genetic analysis for Griscelli syndrome was performed. As the elder sibling had died, mutation analysis was only performed on the younger sibling, which revealed a novel homozygous mutation in the RAB27A gene on chromosome 15 showing a single-base substitution (c.136T>A p.F46I). Both parents were heterozygous for the same mutation. This confirmed the diagnosis of GS2 in the accelerated phase in both siblings. The atypical features of GS2 in these cases are a novel mutation, isolated neurological involvement in one sibling, association with erythema nodosum, and 2 distinct clinical presentations in siblings with the same genetic mutation.