title: A modified MS-PCR approach to diagnose patients with Prader-Willi and Angelman syndrome.
abstract: Prader-Willi (PWS) and Angelman (AS) syndromes are clinically distinct neurodevelopmental genetic diseases with multiple phenotypic manifestations. They are one of the most common genetic syndromes caused by non-Mendelian inheritance in the form of genomic imprinting, and can be attributable to the loss of gene expression due to imprinting within the chromosomal region 15q11-q13. Clinical diagnosis of PWS and AS is challenging, and the use of molecular and cytomolecular studies is recommended to help in determining the diagnosis of these conditions. The methylation analysis is a sensible approach; however there are several techniques for this purpose, such as the methylation-sensitive polymerase chain reaction (MS-PCR). This study aims to optimize the MS-PCR assay for the diagnosis of potential PWS and AS patients using DNA modified by sodium bisulfite. We used the MS-PCR technique of PCR described by Kosaki et al. (1997) adapted with betaine. All different concentrations of betaine used to amplify the methylated and unmethylated chromosomal region 15q11-q13 on the gene SNRPN showed amplification results, which increased proportionally to the concentration of betaine. The methylation analysis is a technically robust and reproducible screening method for PWS and AS. The MS-PCR assures a faster, cheaper and more efficient method for the primary diagnosis of the SNRPN gene in cases with PWS and AS, and may detect all of the three associated genetic abnormalities: deletion, uniparental disomy or imprinting errors.
authors.affiliation: Laboratory of Human Genetics and Mutagenesis, Institute of Biology, Federal University of Bahia, Barão of Geremoabo Street, 147, Campus Ondina, Salvador, BA, CEP: 40170-290, Brazil.
authors.forename: Jéssica Fernandes
authors.initials: JF
authors.lastname: Dos Santos
authors.affiliation: Laboratory of Human Genetics and Mutagenesis, Institute of Biology, Federal University of Bahia, Barão of Geremoabo Street, 147, Campus Ondina, Salvador, BA, CEP: 40170-290, Brazil.
authors.forename: Laís R
authors.initials: LR
authors.lastname: Mota
authors.affiliation: Laboratory of Human Genetics and Mutagenesis, Institute of Biology, Federal University of Bahia, Barão of Geremoabo Street, 147, Campus Ondina, Salvador, BA, CEP: 40170-290, Brazil.
authors.forename: Pedro Henrique Silva Andrade
authors.initials: PH
authors.lastname: Rocha
authors.affiliation: Laboratory of Human Genetics and Mutagenesis, Institute of Biology, Federal University of Bahia, Barão of Geremoabo Street, 147, Campus Ondina, Salvador, BA, CEP: 40170-290, Brazil. fdelima@ufba.br.
authors.forename: Renata Lúcia L
authors.initials: RL
authors.lastname: Ferreira de Lima
mesh_terms: D017204:Angelman Syndrome / Q000175:diagnosis* / Q000235:genetics; D001622:Betaine / Q000378:metabolism; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics; D019175:DNA Methylation; D018392:Genomic Imprinting; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods*; D011218:Prader-Willi Syndrome / Q000175:diagnosis* / Q000235:genetics; D012680:Sensitivity and Specificity; D055517:snRNP Core Proteins / Q000235:genetics*
chemical_list: C526417:SNRPN protein, human; D055517:snRNP Core Proteins; D001622:Betaine
keywords: Betaine; CpG islands; Enhancers; Genomic imprinting; Molecular diagnosis