Screening of RET gene mutations in multiple endocrine neoplasia type-2 using Conformation Sensitive Gel Electrophoresis (CSGE)

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant inherited tumor syndrome caused by RET proto-oncogene germline mutations (RET). Here we tested the Conformation Sensitive Gel Electrophoresis (CSGE) as a screening method for RET hot-spot mutations. Seven MEN2 families were studied by direct sequencing analysis, CSGE and Single Strand Conformational Polymorphism (SSCP). Using CSGE/SSCP, we were able to detect four out of five types of RET mutations verified by sequencing analysis: Cys620Arg, Cys634Arg, Cys634Tyr, and Met918Thr, furthermore a missense substitution at codon 648 (Val648Ile). RET polymorphisms 691 and 769 were also verified. Data obtained using CSGE/SSCP were fully concordant. We conclude that CSGE showed to be a sensitive, fast, low-cost, and simple procedure to detect RET mutations in codons which are reported as the most prevalent RET variants (~ 95 percent) in large MEN2 series. As to the Val804Met mutation, this method still needs to be optimized.

A neoplasia endócrina múltipla tipo 2 (NEM2) é uma síndrome tumoral herdada por mutações germinativas no proto-oncogene RET (RET). Analisamos a aplicação do método Eletroforese em Gel Sensível à Conformação (CSGE) no rastreamento de mutações hot spots do RET. Sete famílias com NEM2 foram rastreadas pelo seqüenciamento gênico, CSGE e análise do Polimorfismo Conformacional de Cadeia Simples (SSCP). Usando ambas as metodologias de rastreamento, identificamos quatro dos cinco tipos de mutações verificadas pelo seqüenciamento: Cys620Arg, Cys634Arg, Cys634Tyr e Met918Thr, além da variação gênica Val648Ile. Das análises englobando mutações hot spots do RET, 90,6 por cento concordaram com o seqüenciamento genético (incluindo a variação gênica Val648Ile). Polimorfismos nos códons 691 e 769 foram documentados. Os dados obtidos por CSGE/SSCP foram totalmente concordantes. Concluímos que o CSGE revelou ser metodologia sensível, rápida, de fácil execução e baixo custo no rastreamento de mutações nos códons associados à grande maioria (~ 95 por cento) dos pacientes com NEM2.

Genetic Association between Single Nucleotide Polymorphisms on COMT Gene and Schizophrenia in Korean Population / 대한정신약물학회지

OBJECTIVE: This study aimed to explore genetic relation between schizophrenia and COMT gene which plays an important role in metabolizing dopamine, one of the most intriguing neuro-transmitters for schizophrenia. METHODS: 1) Single Nucleotide Polymorphism (SNP) on exons of COMT gene was searched by F-CSGE (Fluorescent-Conformation Sensitive Gel Electrophoresis) method with 50 patients with schizophrenia to look for any SNP unique to Korean patients with schizophrenia. 2) Genotyping was done for five SNPs on COMT gene for 218 patients with schizophrenia and 199 normal controls by SNaPShot method. Allele frequencies, genotype frequencies and simulated haplotype frequencies were compared between patients with schizophrenia and normal controls. RESULTS: 1) No unique SNPs for Koreans was found on exons of COMT gene and seven SNPs were found, all of them are already reported to be found in other ethnic groups. 2) No significant difference between patients with schizophrenia and normal controls in terms of allele frequencies, genotype frequencies and haplotype frequencies was found in our sample. CONCLUSION: Genetic association between five SNPs on COMT gene and DSM-IV diagnosis of schizophrenia among Koreans was not able to be found in this study.