A genome-wide association study of the association between single nucleotide polymorphisms and brachial-ankle pulse wave velocity in healthy Koreans

Xu, EnShi,Shin, Jinho,Lim, Ji Eun,Kim, Mi Kyung,Choi, Bo Youl,Shin, Min-Ho,Shin, Dong Hoon,Lee, Young-Hoon,Chun, Byung-Yeol,Hong, Kyung-Won,Hwang, Joo-Yeon Korean Society of Medical Genetics and Genomics 2017 대한의학유전학회지 Vol.14 No.1

Purpose: Pulse wave velocity (PWV) is an indicator of arterial stiffness, and is considered a marker of vascular damage. However, a genome-wide association study analyzing single nucleotide polymorphisms (SNPs) associated with brachial-ankle PWV (baPWV) has not been conducted in healthy populations. We performed this study to identify SNPs associated with baPWV in healthy populations in Korea. Materials and Methods: Genomic SNPs data for 2,407 individuals from three sites were analyzed as part of the Korean Genomic Epidemiologic Study. Without replication samples, we performed multivariable analysis as a post hoc analysis to verify the findings in site adjusted analysis. Healthy subjects aged between 40 and 70 years without self-reported history or diagnosis of hypertension, diabetes, hyperlipidemia, heart disease, cerebrovascular disease and cancer were included. We excluded subjects with a creatinine level >1.4 mg/dL (men) and 1.2 mg/dL (women). Results: In the site-adjusted association analysis, significant associations (P<$5{\times}10^{-8}$) with baPWV were detected for only 5 SNPs with low minor allele frequency. In multivariable analysis adjusted by age, sex, height, body mass index, mean arterial pressure, site, smoking, alcohol, and exercise, 11 SNPs were found to be associated (P<$5{\times}10^{-8}$) with baPWV. The 5 SNPs (P<$5{\times}10^{-8}$) linked to three genes (OPCML, PRR35 and RAB40C) were common between site-adjusted analysis and multivariable analysis. However, meta-analysis of the result from three sites for the 11 SNPs showed no significant associations. Conclusion: Using the recent standard for genome-wide association study, we did not find any evidence of significant association signals with baPWV.

A case of maternal uniparental disomy of chromosome 20 detected by noninvasive prenatal test of 1,000 high-risk pregnancies

Cha, Dong Hyun,Lee, Junnam,Jeon, Young-Joo,Jung, Yong Wook,Jang, Ja-Hyun,Lee, Taeheon,Cho, Eun Hae Korean Society of Medical Genetics and Genomics 2017 대한의학유전학회지 Vol.14 No.1

Chromosomal loss in trisomy (trisomy rescue) to generate a disomic fetus can cause confined placental mosaicism and/or feto/placental mosaicism. After trisomy rescue event, there is a risk of fetal uniparental disomy (UPD). Noninvasive prenatal test (NIPT) reflects the genomic constitution of the placenta, not of the fetus itself. Feto-placental discrepancy can therefore cause false-positive (trisomy) NIPT results. These discordant NIPT results can serve as important clues to find UPD associated with confined placental mosaicism. We report a case with maternal UPD of chromosome 20, detected by NIPT of 1,000 high-risk pregnancies, carried out for detecting chromosomal abnormalities in Koreans.

A case of Mowat-Wilson syndrome with developmental delays and Hirschsprung's disease

Lee, Darae,Kim, Ja Hye,Cho, Ja Hyang,Oh, Moon-Yun,Lee, Beom Hee,Kim, Gu-Hwan,Choi, Jin-Ho,Yoo, Han-Wook Korean Society of Medical Genetics and Genomics 2014 대한의학유전학회지 Vol.11 No.2

Mowat-Wilson syndrome is an extremely rare genetic disease that is characterized by intellectual disability, facial dysmorphism, Hirschsprung's disease, and other congenital anomalies. This disorder is caused by heterozygous mutations or deletions in the zinc finger E-box-binding homeobox-2 gene (ZEB2). Thus far, approximately 200 cases of Mowat-Wilson syndrome have been reported worldwide. In Korea, only one case with a 2q22 deletion, which also affects ZEB2, has been previously reported. Here, we describe a patient with Mowat-Wilson syndrome who presented with developmental delays, typical facial dysmorphism, and Hirschsprung's disease. Molecular analysis of ZEB2 identified a novel heterozygous mutation at c.190dup ($p.S64Kfs^*6$). To our knowledge, this is the second report of a Korean patient with Mowat-Wilson syndrome that has been confirmed genetically.

Genetics of Mitochondrial Myopathies

Shin, Jin-Hong,Kim, Dae-Seong Korean Society of Medical Genetics and Genomics 2013 대한의학유전학회지 Vol.10 No.1

Mitochondrion is an intracellular organelle with its own genome. Its function in cellular metabolism is indispensable that mitochondrial dysfunction gives rise to multisystemic failure. The manifestation is most prominent with tissues of high energy demand such as muscle and nerve. Mitochondrial myopathies occur not only by mutations in mitochondrial genome, but also by defects in nuclear genes or secondarily by toxic insult on mitochondrial replication. Currently curative treatment modality does not exist and symptomatic treatment remains mainstay. Administration of L-arginine holds great promise according to the recent reports. Advances in mitochondrial RNA import might enable a new therapeutic strategy.

West syndrome with hyperkinesia and cortical visual impairment: A case report of GRIN1 encephalopathy

Choi, Seul A,Kim, Young Ok Korean Society of Medical Genetics and Genomics 2021 대한의학유전학회지 Vol.18 No.1

West syndrome (WS) presenting with infantile spasms, developmental delay, and hypsarrhythmia has genetic etiology in some patients. Movement disorders or visual impairment that share genetic underpinnings with infantile spasms can provide diagnostic clues for specific genetic mutations. Mutations of the GRIN1 gene encoding the glutamate receptor inotropic N-methyl-D-aspartate subunit can result in WS with hyperkinetic movements, cortical visual impairment, autistic features, and bilateral polymicrogyria. An 11-month-old boy with WS showed hyperkinetic movements and visual impairment. Brain magnetic resonance imaging and metabolic investigations revealed no abnormalities. Whole-exome sequencing revealed a novel likely pathogenic variant (c.1561_1563del; p.Asn521del) of GRIN1 (NM_007327.3). The proband was treated with vigabatrin and became seizure-free within one week. Notably, the cortical blindness improved within 3 months and the hyperkinetic movements resolved one year after the proband became seizure-free. To the best of our knowledge, this is the first report of GRIN1 encephalopathy in Koreans.

Analysis of trinucleotide repetitive sequences for Korean patients with spinocerebellar ataxia types 8, 12, and 17

Kim, Gu-Hwan,Chung, Sun Ju,Ryu, Ho-Sung,Kim, Jaemin,Lee, Jin-Joo,Choi, Seoung Hoon,Lee, Juyeon,Lee, Beom Hee,Choi, Jin-Ho,Yoo, Han-Wook Korean Society of Medical Genetics and Genomics 2015 대한의학유전학회지 Vol.12 No.1

Purpose: Spinocerebellar ataxias (SCAs) are progressive neurodegenerative disorders with diverse modes of inheritance. There are several subtypes of SCAs. SCA 8, SCA 12, and SCA 17 are the less common forms of SCAs with limited information available on their epidemiological profiles in Korea. The purpose of this study was to investigate the prevalence of SCA8, SCA12, and SCA17 in Korea. Materials and Methods: Ninety-six unrelated Korean patients were enrolled and showed normal trinucleotide repeats through polymerase-chain reaction (PCR) for the genes ATXN1, ATXN2, ATXN3, CACNA1A, and ATXN7, which correspond to SCA1, SCA2, SCA3, SCA6, and SCA7, respectively. PCR products from patients were further analyzed by capillary electrophoresis using fluorescence labeled primers for the genes ATXN8OS, PPP2R2B, and TBP, which correspond to SCA8, SCA12, and SCA17. Results: Three patients had 104, 97, and 75 abnormal expanded repeats in the ATXN8OS gene, the causative gene for SCA8. None of the patients exhibited abnormal repeats in SCA12 and SCA17. Normal trinucleotide repeat ranges of the cohort in this study were estimated to be 17-34 copies (average, $24{\pm}4copies$) for SCA8, 7-18 copies (average, $13{\pm}3copies$) for SCA12, and 26-43 copies (average, $35{\pm}2copies$) for SCA17. Conclusion: This study demonstrated that SCA8, SCA12, and SCA17 are rare in Korean patients with SCA, and further genetic studies are warranted to enhance the mutation detection rate in the Korean SCA population.

Clinical and genetic characteristics of Korean patients with IARS2-related disorders

Lee, Jin Sook,Kim, Man Jin,Kim, Soo Yeon,Lim, Byung Chan,Kim, Ki Joong,Choi, Murim,Seong, Moon-Woo,Chae, Jong-Hee Korean Society of Medical Genetics and Genomics 2019 대한의학유전학회지 Vol.16 No.2

Purpose: Genetic defects in the nuclear-encoded mitochondrial aminoacyl-tRNA synthetases were first identified as causes of various disorders in 2007. Variants in IARS2, which encodes a mitochondrial isoleucyl-tRNA synthetase, were first reported in 2014. These variants are associated with diverse phenotypes ranging from CAGSSS (CAtaracts, Growth hormone deficiency, Sensory neuropathy, Sensorineural hearing loss, and Skeletal dysplasia) and Leigh syndrome to isolated nonsyndromic cataracts. Here, we describe the phenotypic and genetic spectrum of Korean patients with IARS2-related disorders. Materials and Methods: Using whole-exome sequencing followed by Sanger sequencing, we identified five patients with IARS2 mutations. Their medical records and brain magnetic resonance images were reviewed retrospectively. Results: All five patients presented with developmental delay or regression before 18 months of age. Three patients had bilateral cataracts, but none had hearing loss or sensory neuropathy. No evidence of skeletal dysplasia was noted, but two had short stature. One patient had cardiomyopathy and another exhibited renal tubulopathy and hypoparathyroidism. Their brain imaging findings were consistent with Leigh syndrome. Interestingly, we found the recurrent mutations p.R817H and p.V105Dfs*7 in IARS2. Conclusion: To our knowledge, this is the first report of Korean patients with IARS2-related disorders. Our findings broaden the phenotypic and genotypic spectrum of IARS2-related disorders in Korea and will help to increase clinical awareness of IARS2-related neurodegenerative diseases.

Genetic and clinical characteristics of Korean patients with neurofibromatosis type 2

Kim, Hye-ji,Seo, Go Hun,Kim, Yoon Myung,Kim, Gu-Hwan,Seo, Eul-Ju,Ra, Young-Shin,Choi, Jin-Ho,Yoo, Han-Wook,Lee, Beom Hee Korean Society of Medical Genetics and Genomics 2017 대한의학유전학회지 Vol.14 No.2

Purpose: Neurofibromatosis type 2 (NF2) is characterized by multiple tumors, including vestibular schwannoma (VS) and others affecting cranial and peripheral nerves. NF2 is caused by mutation of the NF2 gene. The mutation spectrum of NF2 has not been characterized in Korean patients. In the current study, the clinical and genetic characteristics of Korean NF2 patients were analyzed. Materials and Methods: Twenty-five unrelated Korean families were enrolled according to the Manchester criteria. Genetic analysis was performed by direct sequencing and multiplex ligation-dependent probe amplification methods using genomic DNA from peripheral lymphocytes or tumor tissues. Results: All patients had bilateral/unilateral VS and/or other cranial and peripheral nerve tumors. Two patients were familial cases and the other 24 patients were sporadic. Germline NF2 mutations were detected in peripheral lymphocytes from both familial cases, but only in 26.1% of the 23 sporadic families. Somatic mutations were also found in tumor tissues from two of the sporadic families. These somatic mutations were not found in peripheral lymphocytes. A total of 10 different mutations including 2 novel mutations were found in 40.0% of studied families. Five mutations (50.0%) were located in exon 6 of NF2, the FERM domain coding region. Conclusion: Family history was an important factor in identifying germline NF2 mutations. Further study is required to investigate whether exon 6 is a mutation hotspot in Korean NF2 patients and its correlation to phenotypic severity.

Genetic Polymorphism in Corticotropin-releasing Hormone Receptor Type-1 in Preeclamptic Korean Women

Lim, Ji-Hyae,Kim, Shin-Young,Park, So-Yeon,Kim, Do-Jin,Kim, Mi-Jin,Ahn, Hyun-Kyong,Han, Jung-Yeol,Kim, Moon-Young,Park, Hyun-Young,Lee, Kwang-Soo,Kim, Young-Ju,Ryu, Hyun-Mee Korean Society of Medical Genetics and Genomics 2011 대한의학유전학회지 Vol.8 No.2

목적: Corticotropin-releasing hormone receptor type 1(CRHR1)은 자간전증과 같은 비정상적인 태반의 기능을 가지는 산모에서 감소되어 나타나며, 그것의 발현이나 기능은 유전적으로 영향을 받는다. 이번 연구의 목표는 한국인에서 CRHR1 유전자 다형성인 c.33+8199C>T과 자간전증 사이의 연관성을 조사하는 것이었다. 대상 및 방법: CRHR1 유전자 다형성은 SNapShot kit와 ABI Prism3100 Genetic analyzer를 이용하여 203명의 자간전증 임산부와 211명의 정상 임산부에서 측정되었고, 유전자 다형성과 자간전증 위험도 사이의 연관성을 분석하였다. 결과: CRHR1 유전자 다형성의 유전자형과 대립유전자 빈도는 자간전증 임산부와 정상 임산부 사이에 다르지 않았다. 자간전증 발생 위험도는 분석된 유전자 다형성의 드문 대립 형질(C)을 지닌 이종접합 유전자형(TC)이나 동형접합 유전자형(CC)을 수반하는 그룹에서 증가되지 않았다. CRHR1 유전자의 동형접합 유전자형(CC)을 수반하는 그룹에서 중증 자간전증과 조기 자간전증과 같은 자간전증의 합병증 발병 위험에도 차이가 없었다. 결론: 이 연구는CRHR1 유전자 다형성인 c.33+8199C>T가 한국인 임신부의 자간전증 발생과 연관이 없음을 나타낸다. Purpose: Placental corticotropin-releasing hormone receptor type 1 (CRHR1) expression is reduced in pregnancies with abnormal placental function such as preeclampsia (PE), and the levels and/or function of CRHR1 are genetically influenced. The aim of this study was to investigate the association between the c.33+8199C>T polymorphism in the CRHR1 gene and PE in a Korean population. Materials and Methods: Using a case-control design, the association between the CRHR1 polymorphism and the risk of PE was investigated in 203 individuals with PE and 211 normotensive controls. Genotypes were determined using a SNapShot kit and an ABI Prism 3100 Genetic analyzer. Results: Genotypes and allele frequencies for the CRHR1 polymorphism did not differ between PE and normotensive pregnancies. The variant T allele was more frequent than the ancestral C allele in both of the groups and was more frequent in the controls than in the cases. In risk analysis for PE, there was not an increased risk of preeclampsia in subjects who were concomitant homozygous rare allele genotypes (CC) (OR, 0.3; P=0.15) or heterozygous rare allele genotypes (TC) (OR, 0.8; P=0.29). There were no differences in the complications of PE such as severity or preterm delivery in patients with the CRHR1 polymorphism. Conclusion: Our findings indicate that the CRHR1 polymorphism was not associated with PE in the present Korean study group.

Psychological effects and risk perception after genetic counseling

Shin, Sunghwan,Ryu, Mi Ra,Kwon, Won Kyung,Kim, Suhee,Jang, Ja-Hyun,Kim, Jong-Won Korean Society of Medical Genetics and Genomics 2021 대한의학유전학회지 Vol.18 No.1

Purpose: Demand for genetic counseling on cancer predisposition syndrome is increasing. We evaluated the psychological effect on counselees after genetic counseling at a clinic in a single center. Materials and Methods: We surveyed a total of 72 enrolled participants who visited a genetic counseling clinic at the Samsung Medical Center (SMC). The initial survey was conducted before the first genetic counseling session, and the second survey was conducted after the second genetic counseling session. A total of 43 participants completed both the initial and second surveys. Results: The initial survey of 72 participants indicated higher feelings of guilt in the group with religion, higher depression and anxiety in the group with a diagnosis of self, and higher anxiety in the group on self-referral to the genetic counseling clinic. In the completed survey of 43 participants, overall decreased depression was observed after the second genetic counseling session (P=0.013). Risk perception and anxiety decreased in the group diagnosed with benign variant/variant of uncertain significance (BV/VUS, 25/3) and increased in the group diagnosed with pathogenic variant (PV, 15). Risk perception and anxiety differed between the BV/VUS and PV groups (P<0.001 and P=0.03, respectively). Conclusion: The genetic counseling clinic at the SMC was effective in ameliorating the depression score. Assessment of survey results revealed different depression scores, feelings of guilt and anxiety, and different effects of the genetic counseling clinic, depending on the subgroups. Understanding the needs and psychological characteristics of different groups is necessary for improving genetic counseling services.