• BMB Reports
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• 제46권5호
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• pp.270-275
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• 2013

It is essential to analyze rare mutations in many fields of biomedical research. However, the detection of rare mutations is usually failed due to the interference of predominant wild-type DNA surrounded. Herein we describe a sensitive and facile method of detecting rare point mutation on the basis of allele-specific amplification in emulsion PCR. The identification and selective amplification of rare mutation are accomplished in one-pot reaction. The allele-specific primers coupled on magnetic beads allow the exclusive amplification and enrichment of the mutant amplicons. The productive beads bearing mutant amplicons are subsequently stained with the fluorescent dyes. Thus, the rare point mutations with a percentage as low as 0.1%, can be detected by fluorescent analysis. The relative percentages of mutation among different samples can be roughly accessed by counting the fraction of fluorescent positive beads through flow cytometry.

• Childhood Kidney Diseases
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• 제24권2호
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• pp.131-137
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• 2020

Nephrogenic diabetes insipidus (DI) is a rare disease in which the patient cannot concentrate urine despite appropriate or high secretion of antidiuretic hormone. Congenital nephrogenic DI is caused by the arginine vasopressin receptor 2 (AVPR2) or aquaporin 2 (AQP2) gene mutation; the AVPR2 genetic mutation accounts for 90% of the cases. National health screening for infants and children was launched in 2007 in order to prevent accidents and promote public health in infants and children in Korea. The program has been widely used as a primary clinical service in Korea. We treated an infant with faltering growth and delayed development detected by the National health screening program, and diagnosed the problem as nephrogenic DI caused by a rare missense mutation of c.490T>C on the AVPR2 gene. This case can be a good educational nephrogenic DI with a rare AVPR2 mutation, which was well screened and traced by the national health screening program for infants and children in Korea.

• Journal of Genetic Medicine
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• 제15권1호
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• pp.24-27
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• 2018

Cornelia de Lange syndrome (CdLS) is a rare, clinically and genetically heterogeneous, multi-system developmental disorder caused by mutations in genes that encode components of the cohesin complex. X-linked CdLS caused by an SMC1A mutation is an extremely rare disease characterized by phenotypes milder than those of classic CdLS. In the Republic of Korea, based on a literature review, one family with SMC1A-related CdLS with mild phenotypes has been genetically confirmed to date. In this study, we describe the clinical features of a Korean boy with a hemizygous novel missense mutation and his mother with a heterozygous mutation, i.e., c.2447G>A (p.Arg816His) in SMC1A, identified by multi-gene panel sequencing. The proband had a mild phenotype with typical facial features and his mother exhibited a mild, subclinical phenotype. This study expands the clinical spectrum of patients with X-linked CdLS caused by SMC1A variants. Moreover, these findings reinforce the notion that a dominant negative effect in a carrier female with a heterozygous mutation in SMC1A results in a phenotype milder than that in a male patient with the same mutation.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제20권1호
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• pp.61-64
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• 2017

Recurrent acute pancreatic attacks is a rare clinical condition (2-5% of all acute pancreatis) in children and is mainly idiopathic in most cases. Sometimes it may be associated with congenital anomalies, metabolic diseases or hereditary conditions. Isovaleric acidemia (IVA) is a rare autosomal recessive amino acid metabolism disorder associated with isovaleryl coenzyme A dehydrogenase deficiency presenting the clinical findings such metabolic acidosis with increased anion gap, hyperammonemia, ketonemia, hypoglycemia, "the odor of sweaty feet," abdominal pain, vomiting, feeding intolerance, shock and coma. Recurrent acute pancreatitis associated with IVA have been rarely reported. Herein; we report a child who admitted with recurrent acute pancreatic attacks and had the final diagnosis of IVA. Mutation analysis revealed a novel homozygous mutation of (p.E117K [c.349G>A]) in the IVA gene. Organic acidemias must kept in mind in the differential diagnosis of recurrent acute pancreatic attacks in children.

• Journal of Genetic Medicine
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• 제13권1호
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• pp.55-58
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• 2016

Pseudomyxoma peritonei (PMP) is a rare tumor that usually originates in the appendix, but a small number of cases originate in the ovary. Lynch syndrome (LS) is an autosomal dominant hereditary condition that increases the risk of cancer, particularly in the colon and endometrium. Mutations in the mismatch repair genes (MSH2, MLH1, MSH6, and PMS2) increase the risk of LS. Reported PMP cases with hereditary gene mutations of unknown significance are also rare. Here, we investigated a PMP patient and her family members, who have an MSH2 variant of unknown significance. Physicians have an important role in counseling, management, and surveillance based on genetics and pathogenicity.

• Journal of Genetic Medicine
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• 제16권1호
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• pp.27-30
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• 2019

Smith-Kingsmore syndrome (SKS; OMIM 616638), also known as macrocephaly-intellectual disability-neurodevelopmental disorder-small thorax syndrome (MINDS; ORPHA 457485), is a rare autosomal dominant disorder, the prevalence of which is not known. It is caused by a heterozygous germline mutation in MTOR (OMIM 601231). Ten different MTOR germline mutations in 27 individuals have been reported in the medical literature to date. These were all gain-of-function missense variants, and about half of the 27 individuals had c.5395G>A p.(Glu1799Lys) in MTOR. Here, I report for the first time a Korean patient with the heterozygous germline mutation c.5395G>A p.(Glu1799Lys) in MTOR. It was found to be a de novo mutation, which was identified by whole-exome sequencing and confirmed by Sanger sequencing. The patient showed typical clinical features of SKS, including macrocephaly/megalencephaly; moderate intellectual disability; seizures; behavioral problems; and facial dysmorphic features of curly hair, frontal bossing, midface hypoplasia, and hypertelorism.

• Journal of Genetic Medicine
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• 제16권1호
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• pp.15-18
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• 2019

SHORT syndrome is an extremely rare congenital condition due to a chromosomal mutation of the PIK3R1 gene found at 5q13.1. SHORT is a mnemonic representing six manifestations of the syndrome: (S) short stature, (H) hyperextensibility of joints and/or inguinal hernia, (O) ocular depression, (R) Rieger anomaly, and (T) teething delay. Other key aspects of this syndrome not found in the mnemonic include lipodystrophy, triangular face with dimpled chin (progeroid facies, commonly referred to as facial gestalt), hearing loss, vision loss, insulin resistance, and intrauterine growth restriction (IUGR). 3q duplication syndrome is rare syndrome that occurs due to a gain of function mutation found at 3q25.31-33 that presents with a wide array of manifestations including internal organ defects, genitourinary malformations, hand and foot deformities, and mental disability. We present a case of a 2 year and 3 month old male with SHORT syndrome and concurrent 3q duplication syndrome. The patient presented at birth with many of the common manifestations of SHORT syndrome such as bossing of frontal bone of skull, triangular shaped face, lipodystrophy, micrognathia, sunken eyes, and thin, wrinkled skin (progeroid appearance). Additionally, he presented with findings associated with 3q duplication syndrome such as cleft palate and cryptorchidism. Although there is no specific treatment for these conditions, pediatricians should focus on referring patients to various specialists in order to treat each individual manifestation.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제20권1호
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• pp.65-70
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• 2017

Bannayan-Riley-Ruvalcaba syndrome (BRRS) is one of the phosphatase and tensin homolog hamartoma tumor syndrome with a PTEN gene mutation. It is a rare dominant autosomal disorder characterized by cutaneous lipomas, macrocephaly, intestinal polyps, and developmental delay. Diagnosing this syndrome is important, because it may represent the pediatric phenotype of Cowden syndrome, in which there is an increased risk for malignant tumors in children. Until now, the prevalence of BRRS is unknown. Several dozen cases have been reported in the medical literature, but no case has been reported in Korea. Here we report a case of a 19-year-old girl who was diagnosed with BRRS because of macrocephaly, intellectual disability, and intestinal polyps. Her mother had similar findings and a PTEN mutation. Neither patient had mutations detected by conventional mutation-detection techniques, but a PTEN gene deletion was demonstrated by chromosomal microarray analysis.

• 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.

• Clinical and Experimental Pediatrics
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• 제53권7호
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• pp.774-777
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• 2010

Pfeiffer syndrome is a rare autosomal dominant disorder characterized by coronal craniosynostosis, brachycephaly, mid-facial hypoplasia, and broad and deviated thumbs and great toes. Pfeiffer syndrome occurs in approximately 1:100,000 live births. Clinical manifestations and molecular genetic testing are important to confirm the diagnosis. Mutations of the fibroblast growth factor receptor 1 ($FGFR1$) gene or $FGFR2$ gene can cause Pfeiffer syndrome. Here, we describe a case of Pfeiffer syndrome with a novel c833_834GC>TG mutation (encoding Cys278Leu) in the $FGFR2$ gene associated with a coccygeal anomaly, which is rare in Pfeiffer syndrome.