• Journal of Genetic Medicine
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• v.16 no.1
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• pp.23-26
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• 2019

Thrombophilia refers to inherited or acquired hemostatic disorders that result in a predisposition to blood clot formation. When combined with the hypercoagulable state that is characteristic of pregnancy, there is an increased risk of severe and recurrent pregnancy complications. Activated protein C resistance caused by factor V Leiden (FVL) mutation is known to be the most common cause of inherited thrombophilia in Caucasian population. FVL mutation has been related to pregnancy complications associated with hypercoagulation, e.g. miscarriage, intrauterine fetal demise, placental abruption, and intrauterine growth retardation. Although the FVL mutation is easily detected using molecular DNA techniques, patients who are heterozygous for this disorder often remain asymptomatic until they develop a concurrent prothrombotic condition. Because there are potentially serious effects of FVL mutation for pregnancy, and because effective treatment strategies exist, early detection and treatment of this condition might be considered.

• Clinical and Experimental Pediatrics
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• v.59 no.sup1
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• pp.157-160
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• 2016

Coexistence of paroxysmal kinesigenic dyskinesia (PKD) with benign infantile convulsion (BIC) and centrotemporal spikes (CTS) is very rare. A 10-year-old girl presented with a 3-year history of frequent attacks of staggering while laughing and of suddenly collapsing while walking. Interictal electroencephalogram (EEG) revealed bilateral CTS, but no changes in EEG were observed during movement. The patient's medical history showed afebrile seizures 6 months after birth, while the family history showed that the patient's mother and relatives on the mother's side had similar dyskinesia. Genetic testing demonstrated that the patient had a heterozygous mutation, c.649_650insC, in the PRRT2 gene. To our knowledge, this constitutes only the second report of a patient with PKD, BIC, CTS, and a PRRT2 mutation.

• Journal of Genetic Medicine
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• v.15 no.2
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• pp.97-101
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• 2018

Tricho-rhino-phalangeal syndrome (TRPS) is a hereditary disorder characterized by craniofacial and skeletal abnormalities. A mutation of the TRPS1 gene leads to TRPS type I or type III. A 20-year-old male patient visited our neurologic department with chronic fatigue. He presented with short stature, sparse hair, pear-shaped nose, and brachydactyly. Radiologic study showed short metacarpals, metatarsals with cone-shaped epiphyses, hypoplastic femur and hip joint. Panel sequencing for OMIM (Online Mendelian Inheritance in Man) listed genes revealed a de novo heterozygous frameshift mutation of c.1801_1802delGA (p.Arg601Lysfs*3) of exon 4 of the TRPS1 gene. The diagnosis of TRPS can be challenging due to the rarity and variable phenotype of the disease, clinicians should be aware of its characteristic clinical features that will lead a higher rate of diagnosis.

• Clinical and Experimental Pediatrics
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• v.54 no.4
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• pp.179-182
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• 2011

Transient neonatal diabetes mellitus (TNDM) is a rare form of diabetes mellitus that presents within the first 6 months of life with remission in infancy or early childhood. TNDM is mainly caused by anomalies in the imprinted region on chromosome 6q24; however, recently, mutations in the ABCC8 gene, which encodes sulfonylurea receptor 1 (SUR1), have also been implicated in TNDM. Herein, we present the case of a male child with TNDM whose mutational analysis revealed a heterozygous c.3547C>T substitution in the ABCC8 gene, leading to an Arg1183Trp mutation in the SUR1 protein. The parents were clinically unaffected and did not show a mutation in the ABCC8 gene. This is the first case of a de novo ABCC8 gene mutation in a Korean patient with TNDM. The patient was initially treated with insulin and successfully switched to sulfonylurea therapy at 14 months of age. Remission of diabetes had occurred at the age of 16 months. Currently, the patient is 21 months old and is euglycemic without any insulin or oral hypoglycemic agents. His growth and physical development are normal, and there are no delays in achieving neurological and developmental milestones.

• Journal of Genetic Medicine
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• v.14 no.2
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• pp.71-74
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• 2017

Mutations in the DNA methyltransferase 1 gene (DNMT1) were reported to cause two phenotypes: OMIM 604121 and OMIM 614116. The first phenotype includes autosomal dominant cerebellar ataxia, deafness, and narcolepsy, which were reported to be caused by mutations in exon 21. The second phenotype includes hereditary sensory and autonomic neuropathy type 1E, which was suggested to be caused by mutations in exon 20 and 21. In this article, we report a novel heterozygous missense variant c.898A>C, p.(Lys300Gln) in exon 12 of DNMT1 in a young woman who presented with pure cerebellar ataxia. This report indicates that a mutation in exon 12 may lead to pure cerebellar ataxia. Another possibility is that the patient is currently in an early stage of the disease, and as the disease progresses, she will have more manifestations. To confirm or exclude this possibility, a subsequent follow-up study reporting the disease progression in this patient may be needed. Further reports of cases with the same mutation are needed to confirm the phenotype of this mutation.

• Clinical and Experimental Pediatrics
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• v.59 no.sup1
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• pp.103-106
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• 2016

Bartter syndrome (BS) is an inherited renal tubular disorder characterized by low or normal blood pressure, hypokalemic metabolic alkalosis, and hyperreninemic hyperaldosteronism. Type III BS is caused by loss-of-function mutations in CLCNKB encoding basolateral ClC-Kb. The clinical phenotype of patients with CLCNKB mutations has been known to be highly variable, and cases that are difficult to categorize as type III BS or other hereditary tubulopathies, such as Gitelman syndrome, have been rarely reported. We report a case of a 10-year-old Korean boy with atypical clinical findings caused by a novel CLCNKB mutation. The boy showed intermittent muscle cramps with laboratory findings of hypokalemia, severe hypomagnesemia, and nephrocalcinosis. These findings were not fully compatible with those observed in cases of BS or Gitelman syndrome. The CLCNKB mutation analysis revealed a heterozygous c.139G>A transition in exon 13 [p.Gly(GGG)465Glu(GAG)]. This change is not a known mutation; however, the clinical findings and in silico prediction results indicated that it is the underlying cause of his presentation.

• Clinical and Experimental Pediatrics
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• v.57 no.5
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• pp.240-244
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• 2014

Pseudohypoparathyroidism type Ia (PHP Ia) is a disorder characterized by multiform hormonal resistance including parathyroid hormone (PTH) resistance and Albright hereditary osteodystrophy (AHO). It is caused by heterozygous inactivating mutations within the Gs alpha-encoding GNAS exons. A 9-year-old boy presented with clinical and laboratory abnormalities including hypocalcemia, hyperphosphatemia, PTH resistance, multihormone resistance and AHO (round face, short stature, obesity, brachydactyly and osteoma cutis) which were typical of PHP Ia. He had a history of repeated convulsive episodes that started from the age of 2 months. A cranial computed tomography scan showed bilateral calcifications in the basal ganglia and his intelligence quotient testing indicated mild mental retardation. Family history revealed that the patient's maternal relatives, including his grandmother and 2 of his mother's siblings, had features suggestive of AHO. Sequencing of the GNAS gene of the patient identified a heterozygous nonsense mutation within exon 11 (c.637 C>T). The C>T transversion results in an amino acid substitution from Gln to stop codon at codon 213 ($p.Gln213^*$). To our knowledge, this is a novel mutation in GNAS.

• Journal of Genetic Medicine
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• v.15 no.2
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• pp.102-106
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• 2018

Aggrecan is a proteoglycan in the extracellular matrix of growth plate and cartilaginous tissues. Aggrecanopathy has been reported as a genetic cause not only for severe skeletal dysplasia but also for autosomal dominant short stature with normal to advanced bone age. We report a novel heterozygous mutation of ACAN in a Korean family with proportionate short stature identified through targeted exome sequencing. We present a girl of 4 years and 9 months with a family history of short stature over three generations. The paternal grandmother is 143 cm tall (-3.8 as a Korean standard deviation score [SDS]), the father 155 cm (-3.4 SDS), and the index case 96.2 cm (-2.9 SDS). Evaluation for short stature showed normal growth hormone (GH) peaks in the GH provocation test and a mild delayed bone age for chronological age. This subject had clinical characteristics including a triangular face, flat nasal bridge, prognathia, blue sclerae, and brittle teeth. The targeted exome sequencing was applied to detect autosomal dominant growth palate disorder. The novel variant c.910G>A (p.Asp304Asn) in ACAN was identified and this variant was found in the subject's father using Sanger sequencing. This is the first case of Korean familial short stature due to ACAN mutation. ACAN should be considered for proportionate idiopathic short stature, especially in cases of familial short stature.

• Annals of Clinical Neurophysiology
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• v.11 no.2
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• pp.59-63
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• 2009

Miyoshi myopathy (MM) is caused by the mutations of dysferlin gene (DYSF), which impairs the function of dysferlin protein causing muscle membrane dysfunction. We report a patient showing the MM phenotype who has a sister with LGMD 2B phenotype, along with the results of the immunohistochemical and molecular analyses of the DYSF gene. Immunohistochemical analysis noted negative immunoreactivity against dysferlin. Direct DNA sequencing of whole exons of DYSF gene revealed heterozygous nonsense mutations (c.610C>T + c.2494C>T). To our knowledge, this is the first reported MM case with this very combination of heterozygous mutations.

• Journal of Genetic Medicine
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• v.17 no.1
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• pp.34-38
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• 2020

The term dopa-responsive dystonia (DRD) is used to describe a group of neurometabolic disorders, which are characterized by dystonia, and are typically associated with diurnal fluctuations and respond to levodopa treatment. Autosomal dominant DRD (DYT5a, MIM# 128230) is caused by a heterozygous mutation in the GTP cyclohydrolase 1 (GCH1) gene (MIM# 600225). GCH1 encodes an enzyme, which is involved in the biosynthesis of tetrahydrobiopterin, an essential co-factor for tyrosine hydroxylase. Herein, we report the case of a 16-year-old girl who was diagnosed with DYT5a. She exhibited additional unusual clinical features, including intellectual disability, depression, multiple skeletal anomalies, and short stature, which are not commonly observed in patients with DYT5a. The patient harbored a heterozygous missense variant, c.539A>C, p.Gln180Pro, in the GCH1 gene, which was identified by targeted gene panel analysis using next-generation sequencing.