• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7997-8002
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• 2015

Gene amplification is an important mechanism in the development and progression of cancer. Currently, gene amplification status is generally determined by in situ hybridization (ISH). Multiplex ligation-dependent probe amplification (MLPA) is a PCR-based method that allows copy number detection of up to 50 nucleic acid sequences in one reaction. The aim of the present study was to compare results for HER2, CCND1, MYC and ESR1 gene amplification detected by MLPA with fluorescent in situ hybridization (FISH) and chromogenic in situ hybridization (CISH) as clinically approved methods. Tissue samples of 170 invasive breast cancers were collected. All were ER positive. Tissue samples had previously been tested for HER2 using immunohistochemistry. Amplification of the selected genes were assessed using MLPA, FISH and CISH and results were compared. HER2 MLPA and ISH results were also compared with HER2 immunohistochemistry (IHC) which detects protein overexpression. Amplification of HER2, CCND1, MYC and ESR1 by MLPA were found in 9%, 19%, 20% and 2% of samples, respectively. Amplification of HER2, CCND1, MYC and ESR1 by FISH was noted in 7%, 16%, 16% and 1% of samples, respectively. A high level of concordance was found between MLPA/FISH (HER2: 88%, CCND1: 88%, MYC: 86%, ESR1: 92%) and MLPA/CISH (HER2: 84%). Of all IHC 3+ cases, 91% were amplified by MLPA. In IHC 2+ group, 31% were MLPA amplified. In IHC 1+ group, 2% were MLPA amplified. None of the IHC 0 cases were amplified by MLPA. Our results indicate that there is a good correlation between MLPA, IHC and ISH results. Therefore, MLPA can serve as an alternative to ISH for detection of gene amplification.

• Journal of Genetic Medicine
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• 제6권2호
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• pp.146-154
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• 2009

Multiplex ligation dependent probe amplification (MLPA)은 탐침자를 표적지에 교잡시킨 후, ligation 시키고, 그 산물을 중합효소연쇄반응으로 증폭시킴으로써 표적지의 존재여부 또는 농도를 확인할 수 있는 방법으로, 그 원리가 소개된 이래로 여러 유전자들에 대한 거대결실 및 중복돌연변이에 대한 탐색에 이용되었다. 유전자진단은 질환에 관련된 유전자에 대한 돌연변이를 탐색함으로써 질환을 진단하는 방법으로, 단일유전자 결핍 질환에 대한 유전자진단은 주로 중합효소연쇄반응과 염기서열 분석 방법을 통한 점돌연변이의 탐색에 집중되어 있다. 거대결실 또는 중복돌연변이의 경우, 특히 이형접합자를 형성하게 되는 경우는 중합효소 연쇄반응을 통하여 결실 또는 중복돌연변이 여부의 확인이 힘들다. PCR 방법에 기초하여 유전자의 농도(gene dosage)를 알 수 있는 방법으로 MLPA 방법이 소개되면서 거대결실 또는중복돌연변이를 포함하고 있던 질병 관련돌연변이들의 규명이 한층 쉬워졌다. MLPA의 원리를 응용하여 단순한 유전자의 농도 측정뿐 아니라 유전자내의 메칠화양상의 차이를 확인하거나, 염색체의 배수체 이상 등 염색체이상의 돌연변이 규명과, 전체 유전자의 크기가 비교적 커서 거대결실 돌연변이를 많이 동반하는, 주로 우성유전의 암 관련 유전자 돌연변이의 규명에 유용하게 이용된다. MLPA는 상용적인 중합효소연쇄반응으로 확인할 수 없는 유전자의 농도를 효과적으로 규명할 수 있는 방법으로, 적은 양의 주형 DNA만을 사용하고, 한가지의 실험원리로 다양한 응용이 가능하며 high-throughput이 가능한 장점을 가지는 반면, 주형 DNA의 질에 결과의 의존도가 높고, 민족 또는 개인간의 차이를 보일 수 있는 표적 DNA 염기서열 내의 single nucleotide polymorphism (SNP) 등으로 인해 분석의 오류가 생길 수 있으며, 양적 차이를 규명하는 것이므로 수 차례의 대조군 검사가 함께 진행되어야 하는 단점이 있다. 여기서는 MLPA를 이용하여 질병유전자의 돌연변이를 밝힌 사례를 바탕으로 MLPA의 원리와 탐색할 수 있는 돌연변이의 종류, 그리고 이 방법의 장단점에 대해 고찰해 보고자 한다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7621-7628
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• 2013

Human epidermal growth factor receptor (HER) status is an important prognostic factor in breast cancer. There is no globally accepted method for determining its status, and which method is most precise is still a matter of debate. We here analyzed HER2 mRNA expression by quantitative reverse transcription-PCR (qRT-PCR) and HER2 DNA amplification using multiplex ligation-dependent probe amplification (MLPA). In parallel, we performed a routine evaluation of HER2 protein by immunohistochemistry (IHC). To assess the accuracy of the RT-PCR and MLPA techniques, a combination of IHC and fluorescence in situ hybridization (FISH) was used, substituting FISH when the results of IHC were ambiguous (2+) and for those IHC results that disagreed with MLPA and qRT-PCR, this approach being termed IHC-FISH. The IHC results for four samples were not compatible with the MLPA and qRT-PCR results; the MLPA and qRT-PCR results for these samples were confirmed by FISH. The correlations between IHC-FISH and qRT-PCR or MLPA were 0.945 and 0.973, respectively. The ASCO/CAP guideline IHC/FISH correlation with MLPA was (0.827) and with RT-PCR was (0.854). The correlations between the IHC results (0, 1+ as negative, and 3+ as positive) and qRT-PCR and MLPA techniques were 0.743 and 0.831, respectively. Given the shortcomings of IHC analysis and greater correlations between MLPA, qRT-PCR, and FISH methods than IHC analysis alone with each of these three methods, we propose that MLPA and real-time PCR are good alternatives to IHC. However a suitable cut-off point for qRTPCR is a prerequisite for determining the exact status of HER2.

• Laboratory Medicine Online
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• 제7권2호
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• pp.83-87
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• 2017

Pseudohypoparathyroidism (PHP) is a rare disorder caused by genetic and epigenetic aberrations in the GNAS complex locus resulting in impaired expression of stimulatory G protein ($Gs{\alpha}$). PHP type Ib (PHP-Ib) is characterized by hypocalcemia and hyperphosphatemia due to renal resistance to the parathyroid hormone, and is distinguished from PHP-Ia by the absence of osteodystrophic features. An 11-yr-old boy presented with poor oral intake and cramping lower limb pain after physical activity. Laboratory studies revealed hypocalcemia, hyperphosphatemia, and increased parathyroid hormone levels. The GNAS complex locus was evaluated using the methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) assay. Gain of methylation in the NESP55 domain and loss of methylation in the antisense (AS) transcript, XL, and A/B domains in the maternal allele were observed. Consequently, we present a case of PHP-Ib diagnosed using MS-MLPA.

• Clinical and Experimental Pediatrics
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• 제53권3호
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• pp.397-407
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• 2010

목 적 : F9 유전자는 혈우병B의 병인 유전자이다. 기존의 RFLP를 이용한 연관분석은 정보제공율이 55.6%에 불과하였다. 직접 염기서열 분석법은 98%의 돌연변이를 진단할 수 있지만, 고가의 비용이 든다. 본 연구는 F9 유전자를 대상으로 돌연변이의 선별검사로써 mPCR-CSGE를 사용하고, 이후 특정 유전자 부위만을 염기서열 분석하여 mPCR-CSGE의 유용성을 확인하기 위해 고안되었다. 방 법 : 연구대상은 비혈연 관계인 27명의 혈우병B 환자였다. 직접염기서열 분석법은 독립된 다른 기관에서 시행하였고, mPCR-CSGE 선별 후 염기서열 분석법은 본 연구자의 기관에서 시행되었다. 직접 염기서열 분석법의 결과가 참고치가 되어 mPCR-CSGE 선별 후 염기서열 분석법을 정확성, 경제성, 신속성, 편이성 측면에서 비교하였다. 두가지 방법으로 진단이 되지 않는 환자에게는 MLPA를 이용하여 돌연변이를 발견하였다. 결 과 : 직접 염기서열 분석법으로 26명(96.3%)의 환자에서 돌연변이를 확인할 수 있었다. mPCR-CSGE 선별 후 염기서열 분석법으로는 23명(85.2%)의 환자에서 돌연변이를 찾아낼 수 있었다. 1명의 환자는 MLPA로써 돌연변이를 확인할 수 있었다. 27명의 환자에게 21개의 독립적인 돌연변이가 있었다. mPCR-CSGE 선별 후 염기서열 분석법은 직접 염기서열 분석법에 비해 비용은 55.7%로 줄일 수 있었으나, 실험 단계는 더욱 복잡하였고, 시간도 하루가 더 걸렸으며, 세심한 실험상의 주의가 필요하였다. 결 론 : mPCR-CSGE 선별 후 염기서열 분석법은 85.2%의 높은 돌연변이 선별력을 보이고, 직접 염기서열 분석법의 57.7%의 비용만 소모하였으나, 실험과정에 세한 주의가 요구되었으며, 노동집약적이고, 실험 시간도 하루가 더 소요되었다.

• Journal of Genetic Medicine
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• 제7권2호
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• pp.156-159
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• 2010

염색체의 역위는 균형재배열을 나타내는 구조적 이상 중 하나로 대부분 정상표현형을 나타낸다. 그러나 생식 세포의 감수 분열 단계에서 역위 고리를 만들어 염색체의 결실 또는 중복을 보이는 재조합 염색체가 형성되면 자녀에게 비정상 표현형이 나타나게 된다. 본 증례는 균형전좌를 가진 산모와 그 태아에 대한 정확한 핵형분석을 위해 세포유전학적인 방법과 분자유전학적인 방법을 함께 이용한 증례 보고이다. Trypsin과 Giemsa를 이용한 GTG 분염법의 결과에서 태아는 산모와는 다른 형태의 구조적 이상이 나타났으며, 정확한 분석을 위해 MLPA와 FISH를 시행하였다. 그 결과역위를 보인 9번 염색체 단완 말단 부위의 부분 소실과 13번 염색체에서는 장완 말단 부위의 부분 증폭이 확인되었다. 이는 생식세포의 감수분열시 상동염색체 사이의 교차에 의한 결과로써 드문 재조합 염색체로 판단된다. 따라서 이 태아의 최종 염색체 분석 결과는 46,XY,rec(9)t(9;13)(p22;q32)inv(9)(p12q13)mat로 보고 하였다. 세포유전학적인 방법을 기초로 한 FISH 또는 MLPA 등과 같은 분자유전학적 방법의 적극적인 이용은 복잡한 염색체 이상을 보이는 핵형 분석에 있어서 유용하고 효과적인 방법이라 하겠다.

• 한국동물위생학회지
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• 제39권1호
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• pp.1-6
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• 2016

In this study, Bacillus licheniformis which has been used as probiotics was isolated from Korean traditional fermented soybean. A total of 69 strains were presumptively identified as B. licheniformis by phenotypic methods. Based on PCR amplification and 16S rRNA gene sequencing, the multilocus sequence typing of gyrA and rpoB, followed by phylogenetic analysis was performed. The isolates were distinctly differentiated and found to be closely related to B. amyloliquefaciens, B. subtilis, and B. aerius. The partial 16S rRNA gene sequences of those strains matched those of B. sonorensis (97%) and B. aerius (98%) in the phylogenetic tree. In contrast, multilocus phylogenetic analysis (MLPA) showed that only 61 (86.9%) out of 69 strains were B. licheniformis. The rest of those strains were found to be B. subtilis (5.8%), B. amyloliquefaciens (2.9%), and B. sonorensis (2.9%), respectively. Therefore, our results suggested that since the 16S rRNA gene sequencing alone was not sufficient to compare and discriminate closely related lineages of Bacillus spp., it was required to analyze the MLPA simultaneously to avoid any misleading phenotype-based grouping of these closely related species.

• Journal of Genetic Medicine
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• 제16권2호
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• pp.49-54
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• 2019

Purpose: Potocki-Lupski syndrome (PTLS), is a recently identified, rare genomic disorder. The patients are affected by infantile hypotonia, poor growth and developmental delay. Facial dysmorphism may not be obvious in some patients. PTLS is associated with microduplication at chromosome 17p11.2. In the current study, three Korean patients are reported with their clinical and genetic features. Materials and Methods: The clinical findings of each patient were reviewed. Karyotyping and multiplex ligation-dependent probe amplification (MLPA) analyses were done for genetic diagnoses. Results: All the patients did not have the characteristic dysmorphic features, such as broad forehead, triangular face, asymmetric smile and palpebral fissures. On the other hand, all three patients were affected by variable degree of developmental delay, poor oral intake, failure to thrive, and language development disorders. Chromosome 17p11.2 duplication was identified by conventional karyotyping analysis only in one patient, whereas the other confirmed by MLPA analyses. Conclusion: Delayed development was mostly commonly observed in our patients without distinct dysmorphic facial features. In this respect, genomic screening in patients with developmental delay would identify more cases with PTLS to understand their long-term clinical courses with the development of adequate psychological and rehabilitation education program.

• Clinical and Experimental Pediatrics
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• 제59권1호
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• pp.16-23
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• 2016

Purpose: The 1p36 deletion syndrome is a microdeletion syndrome characterized by developmental delays/intellectual disability, craniofacial dysmorphism, and other congenital anomalies. To date, many cases of this syndrome have been reported worldwide. However, cases with this syndrome have not been reported in Korean populations anywhere. This study was performed to report the clinical and molecular characteristics of five Korean patients with the 1p36 deletion syndrome. Methods: The clinical characteristics of the 5 patients were reviewed. Karyotyping and multiplex ligation-dependent probe amplification (MLPA) analyses were performed for genetic diagnoses. Results: All 5 patients had typical dysmorphic features including frontal bossing, flat right parietal bone, low-set ears, straight eyebrows, down-slanting palpebral fissure, hypotelorism, flat nasal roots, midface hypoplasia, pointed chins, small lips, and variable degrees of developmental delay. Each patient had multiple and variable anomalies such as a congenital heart defect including ventricular septal defect, atrial septal defect, and patent duct arteriosus, ventriculomegaly, cryptorchism, or hearing loss. Karyotyping revealed the 1p36 deletion in only 1 patient, although it was confirmed in all 5 patients by MLPA analyses. Conclusion: All the patients had the typical features of 1p36 deletion. These hallmarks can be used to identify other patients with this condition in their early years in order to provide more appropriate care.

• Journal of Genetic Medicine
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• 제13권1호
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• pp.36-40
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• 2016

Tuberous sclerosis complex (TSC, MIM#191100) is an autosomal dominant neurocutaneous syndrome caused by mutation or deletion of TSC1 encoding hamartin or TSC2 encoding tuberin and characterized by seizure, mental retardation, and multiple hamartomas or benign tumors in the skin, brain, retina, heart, kidney, and lungs. The TSC2 gene on chromosome 16p13.3 lies adjacent to the PKD1 gene which is responsible for autosomal dominant polycystic kidney disease (MIM#173900). The TSC2/PKD1 contiguous gene syndrome (TSC2/PKD1 CGDS, MIM#600273) is caused by deletion of both TSC2 and PKD1 gene. We recently experienced a 15 month-old boy and a 26 month-old girl with TSC2/PKD1 CGDS confirmed by multiplex ligation-dependent probe amplification (MLPA) analysis. They showed not only typical neurologic manifestations of TSC such as epilepsy, subependymal nodules, and subcortical tubers, but also polycystic kidney disease. The contiguous gene syndrome involving PKD1 and TSC2 should be suspected in children with enlarged polycystic kidneys and TSC. MLPA analysis is a useful method for the genetic confirmation of TSC2/PKD1 CGDS.