title: Quantification of various APP-mRNA isoforms and epistasis in Lesch-Nyhan disease.
abstract: The present work is the development of a simple and specific kinetic method based on RT-PCR technique coupled with direct sequencing for quantification of various amyloid precursor protein-mRNA isoforms (APP-mRNA isoforms) in biological samples, especially for identifying the most abundant one that may decisive for the normal status or disease risk. Application of this kinetic method to the Lesch-Nyhan disease (LND) was performed and results indicated an epistasis between mutated hypoxanthine phosphoribosyltransferase1 (HPRT1) and APP genes. APP-mRNA isoform of 624bp, with a deletion starting after 49bp of the 5' end of exon 3 followed by a complete deletion of exons 4-15, mutations in exon 1: c.22C>T, p.L18F, and exon 3: c.269A>G, p.Q90R encoding APP207isoform, was the most abundant one in most of the LND patients and would be responsible for the neurobehavioral syndrome in these patients. The method is useful for identifying the defective APP-mRNA isoform in LND patients, and in neurodevelopmental and neurodegenerative disorders in which the APP gene is involved in the pathogenesis of diseases such as autism, fragile X syndrome, amyotrophic lateral sclerosis, and Alzheimer's disease, and may pave the way for new strategies applicable to rational antisense drugs design.
authors.affiliation: Department of Medicine, Biochemical Genetics and Metabolism, The Mitochondrial and Metabolic Disease Center, School of Medicine, University of California, San Diego, Building CTF, Room C-103, 214 Dickinson Street, San Diego, CA, 92103-8467, USA; Department of Pediatrics, University of California, San Diego, School of Medicine, San Diego, La Jolla, CA, 92093, USA. Electronic address: kvn006@ucsd.edu.
authors.forename: Khue Vu
authors.initials: KV
authors.lastname: Nguyen
authors.affiliation: Department of Pediatrics, University of California, San Diego, School of Medicine, San Diego, La Jolla, CA, 92093, USA.
authors.forename: William L
authors.initials: WL
authors.lastname: Nyhan
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics; D016564:Amyloid beta-Protein Precursor / Q000235:genetics*; D004843:Epistasis, Genetic / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D007926:Lesch-Nyhan Syndrome / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D019636:Neurodegenerative Diseases / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics; D059368:RNA Isoforms / Q000378:metabolism*
chemical_list: D016564:Amyloid beta-Protein Precursor; D020033:Protein Isoforms; D059368:RNA Isoforms; D007041:Hypoxanthine Phosphoribosyltransferase
keywords: Amyloid precursor protein; Epigenetics; Epistasis; Kinetic method; Lesch-Nyhan disease; Neurodevelopmental and neurodegenerative disorders