High-Resolution Physical and Transcriptional Mapping of the Autoimmune Polyendocrinopathy–Candidiasis–Ectodermal Dystrophy Locus on Chromosome 21q22.3 by FISH
- Johanna Aaltonen1,5,
- Nina Horelli-Kuitunen2,5,
- Jian-Bing Fan3,
- Petra Björses1,
- Jaakko Perheentupa4,
- Richard Myers3,
- Aarno Palotie2, and
- Leena Peltonen1,6
- 1Department of Human Molecular Genetics, National Public Health Institute, 00300 Helsinki, Finland; 2Departments of Clinical Chemistry and Biomedicine, University of Helsinki, 00280 Helsinki, Finland; 3Department of Genetics and the Stanford Human Genome Center, Stanford University School of Medicine, Stanford, California 94305; 4Hospital for Children and Adolescents, University of Helsinki, 00280 Helsinki, Finland
Abstract
Autoimmune–polyendocrinopathy–candidiasis–ectodermal dystrophy (APECED, PGD type I) is an autosomal recessive disease enriched in the Finnish population. Previously, we have assigned APECED to a 2.6-cM interval on chromosome 21q22.3 by linkage analysis in 14 Finnish families. This subtelomeric region of 21q22.3 seems to have sequence features resulting in its under-representation in large insert genomic libraries, and only a few large insert clones have been available for positional cloning to date. Here, we report the refined localization of the APECED gene and a visual physical map of 800 kb covering the critical chromosomal region for the gene. In the construction of the physical map, the recently developed fiber FISH techniques were essential for the orientation of the cosmid P1, PAC, and BAC clones in relation to each other. We also localized two cDNAs within this genomic region by fiber FISH combined with the highly sensitive tyramide-based detection method. These data will facilitate the final cloning of theAPECED gene and any other novel gene in this complex genomic region.
[On-line supplement for primer sequences, PCR product size, and annealing temperatures is available athttp://www.cshl.org/gr.]
