• Journal of Genetic Medicine
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• v.11 no.1
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• pp.31-35
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• 2014

Bardet-Biedl syndrome (BBS) is a rare ciliopathy generally inherited with an autosomal recessive pattern. BBS is characterized by 6 primary features namely retinal dystrophy, obesity, postaxial polydactyly, renal dysfunction, learning difficulties, and hypogonadism and a wide range of secondary features. To date, mutations in 16 genes have been identified as causative factors for BBS. Among them, the BBS1 and BBS10 genes are major disease-causing genes, and each of these gene mutations presents in more than 20% of all BBS patients. Genotype-phenotype correlations have not been observed in BBS, and there can be phenotypic overlap between BBS and other ciliopathies. In Korea, no molecular, genetically confirmed case of BBS has been reported to date. Herein, we describe the case of the first Korean siblings with BBS resulting from 2 BBS10 gene mutations who showed typical clinical phenotypes, including retinal dystrophy, obesity, intellectual disability, cystic tubular disease, and postaxial polydactyly.

• Journal of Genetic Medicine
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• v.11 no.1
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• pp.27-30
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• 2014

Brachydactyly type C is a limb malformation characterized by shortening of the second, third, and fifth middle and/or proximal phalanges, but it has variable phenotypic expressivity. Mutations in the growth differentiation factor-5 (GDF5) gene cause isolated brachydactyly C. Herein, we report a familial case with isolated brachydactyly type C characterized by brachymesophalangy of both second and third digits, with a GDF5 missense mutation, and discuss the phenotypic variability of the condition. Identifying more cases with genetic confirmation will help elucidate the clinical and genetic characteristics of this condition in the Korean population.

• Journal of Genetic Medicine
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• v.6 no.1
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• pp.8-24
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• 2009

Understanding the genetic background of hearing loss is important since almost 50% of the cases of profound hearing loss are caused by genetic factors. Until now, more than 150 causative genes have been identified. In this review, classification of genetic hearing loss (syndromic versus non-syndromic, recessive versus dominant, X-linked and mitochondrial), pitfalls in elucidating causative genes, anatomy of the inner ear, introduction of the most common syndromic hearing loss, introduction of the most common non-syndromic hearing loss-causing genes, mitochondrial and multifactorial hearing losses were discussed. Moreover, clinical approaches to the patients with hereditary hearing loss and genetic counseling were also explained briefly. Finally, future directions of the hereditary hearing loss research in Korean population were presented.

• Journal of Genetic Medicine
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• v.10 no.1
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• pp.1-6
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• 2013

Chronic granulomatous disease (CGD) is a rare inherited disorder of a defective NADPH oxidase enzyme, resulting in very low or no production of superoxide and subsequent reactive oxygen species. Consequently, patients with CGD are highly susceptible to severe bacterial and fungal infections. CGD is a genetically heterogeneous disease caused by defects in any one of the genes encoding the NADPH oxidase components. CGD generally affects about 3-4 per 1,000,000 individuals; thus, it is surprising that the prevalence of CGD on Jeju Island is 34.3 per 1,000,000 individuals. At present, 20 patients with CGD from 14 unrelated families on Jeju Island have been identified; nine males and 11 females. All patients with CGD tested on Jeju Island had an identical and homozygous mutation (c.7C>T in CYBA, p.Q3X in $p22^{phox}$). Therefore, all patients were autosomal recessive form of CGD. This strongly suggests that the unique and identical mutation in CYBA may be inherited from a common proband. Using mutation-specific primers to detect the mutated allele in CYBA, the frequency of subjects carrying a mutated allele was 1.3% of enrolled subjects from Seogwipo City. Further studies are necessary to elucidate how frequently this mutant allele occurs in the population on Jeju Island. Additionally, it is important to construct a national registry system to understand the pathophysiology of CGD and develop a strategy for long-term therapy.

• Genomics & Informatics
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• v.14 no.1
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• pp.34-40
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• 2016

Due to advances in omics technologies, numerous genome-wide studies on human samples have been published, and most of the omics data with the associated clinical information are available in public repositories, such as Gene Expression Omnibus and ArrayExpress. While analyzing several public datasets, we observed that errors in gender information occur quite often in public datasets. When we analyzed the gender description and the methylation patterns of gender-specific probes (glucose-6-phosphate dehydrogenase [G6PD], ephrin-B1 [EFNB1], and testis specific protein, Y-linked 2 [TSPY2]) in 5,611 samples produced using Infinium 450K HumanMethylation arrays, we found that 19 samples from 7 datasets were erroneously described. We also analyzed 1,819 samples produced using the Affymetrix U133Plus2 array using several gender-specific genes (X (inactive)-specific transcript [XIST], eukaryotic translation initiation factor 1A, Y-linked [EIF1AY], and DEAD [Asp-Glu-Ala-Asp] box polypeptide 3, Y-linked [DDDX3Y]) and found that 40 samples from 3 datasets were erroneously described. We suggest that the users of public datasets should not expect that the data are error-free and, whenever possible, that they should check the consistency of the data.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6211-6217
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• 2014

Previous genome-wide association studies (GWAS) have implicated several single nucleotide polymorphisms (SNPs) in the AT-rich interactive domain 5B (ARID5B) gene with childhood acute lymphoblastic leukemia (ALL). However, replicated studies reported some inconsistent results in different populations. Using meta-analysis, we here aimed to clarify the nature of the genetic risks contributed by the two polymorphisms (rs10994982, rs7089424) for developing childhood ALL. Through searches of PubMed, EMBASE, and manually searching relevant references, a total of 14 articles with 16 independent studies were included. Odds ratios (ORs) with 95% confidence intervals (95%CI) were calculated to assess the associations. Both SNPs rs10994982 and rs7089424 showed significant associations with childhood ALL risk in all genetic models after Bonferroni correction. Furthermore, subtype analyses of B-lineage ALL provided strong evidence that SNP rs10994982 is highly associated with the risk of developing B-hyperdiploid ALL. These results indicate that SNPs rs10994982 and rs7089424 are indeed significantly associated with increased risk of childhood ALL.

• BMB Reports
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• v.41 no.10
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• pp.685-692
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• 2008

Colorectal cancer (CRC) is the third most common malignancy in the world. Because CRC develops slowly from removable precancerous lesions, detection of the disease at an early stage during regular health examinations can reduce both the incidence and mortality of the disease. Although sigmoidoscopy offers significant improvements in the detection rate of CRC, its diagnostic value is limited by its high costs and inconvenience. Therefore, there is a compelling need for the identification of noninvasive biomarkers that can enable earlier detection of CRC. Accordingly, many validation studies have been conducted to evaluate genetic, epigenetic or protein markers that can be detected in the stool or in serum. Currently, the fecal-occult blood test is the most widely used method of screening for CRC. However, advances in genomics and proteomics combined with developments in other relevant fields will lead to the discovery of novel non invasive biomarkers whose usefulness will be tested in larger validation studies. Here, non-invasive molecular biomarkers that are currently used in clinical settings and have the potential for use as CRC biomarkers are discussed.

• Journal of Genetic Medicine
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• v.13 no.1
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• pp.51-54
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• 2016

Centronuclear myopathy (CNM) is a rare congenital myopathy that is pathologically characterized by the centrally located nuclei in most of the muscle fibers. On clinical examination, dynamin 2 (DNM2)-related CNM typically shows distal dominant muscle atrophy, ptosis, ophthalmoplegia, and contracture. The reported cases of CNM in Caucasian studies show a high prevalence rate of early-onset ptosis and ophthalmoplegia and correlated with the severity of the disease. However, Asian reports show a low prevalence and late-onset ocular symptoms in DNM2-related CNM patients. p.R465W is one of the most commonly found mutations in Western countries, and all the cases showed ocular symptoms. The proband and his daughter had no ocular symptoms despite harboring the same p.R465W mutation. This family makes us speculate that ocular symptoms in DNM2-related CNM are influenced by ethnic background. In addition, this is the first familial case of DNM2-related CNM in Korea.

• Journal of Genetic Medicine
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• v.13 no.1
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• pp.46-50
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• 2016

Achondroplasia and hypochondroplasia are the two most common forms of short-limb dwarfism. They are autosomal dominant diseases that are characterized by a rhizomelic shortening of the limbs, large head with frontal bossing, hypoplasia of the mid-face, genu varum and trident hands. Mutations in the fibroblast growth factor receptor-3 (FGFR3) gene, which is located on chromosome 4p16.3, have been reported to cause achondroplasia and hypochondroplasia. More than 98% of achondroplasia cases are caused by the G380R mutation (c.1138G>A or c.1138G>C). In contrast, the N540K mutation (c.1620C>A) is detected in 60-65% of hypochondroplasia cases. Tests for common mutations are often unable to detect the mutation in patients with a clinical diagnosis of hypochondroplasia. In this study, we presented a case of familial hypochondroplasia with a rare mutation in FGFR3 identified by next generation sequencing.

• Journal of Genetic Medicine
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• v.15 no.1
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• pp.34-37
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• 2018

A 1q21.1 microdeletion is an extremely rare chromosomal abnormality that results in phenotypic diversity and incomplete penetrance. Patients with a 1q21.1 microdeletion exhibit neurological-psychiatric problems, microcephaly, epilepsy, facial dysmorphism, cataract, and thrombocytopenia absent radius syndrome. We reported a neonate with confirmed intrauterine growth restriction (IUGR), micrognathia, glossoptosis, upper airway obstruction, facial dysmorphism, and eye abnormality at birth as well as developmental delay at the age of 1 year. These clinical manifestations, except for the IUGR and upper airway obstruction, in the neonate indicated a 1q21.1 microdeletion. Here, we report a rare case of a 1q21.1 microdeletion obtained via paternal inheritance in a newborn with upper airway obstruction caused by glossoptosis and tracheal stenosis.