Genetic and Physical Mapping of the Progressive Epilepsy with
Mental Retardation (EPMR) Locus on Chromosome 8p
Susanna Ranta1,2,
Anna-Elina Lehesjoki 2,
Aune Hirvasniemi3,
Jean Weissenbach4,
Barbara Ross1,
Suzanne M. Leal1,5,
Albert de la Chapelle2,
and T. Conrad Gilliam 1,6
1
Departments of Psychiatry and Genetics and Development,
College of Physicians and Surgeons at Columbia University
and New York State Psychiatric Institute, New York, New York 10032;
2
Department of Medical Genetics, University of Helsinki, Finland;
3
Department of Pediatrics, Kainuu Central Hospital, Kajaani, Finland;
4
Genethon, Evry, France;
5
Department of Otolaryngology, University of Tubingen, Germany
6
Corresponding author. email: tcg1@columbia.edu; FAX 212-781-2661.
Genome Research, Volume 6, Issue 5, 351-360 (May 1996)
Abstract
Progressive epilepsy with mental retardation (EPMR) is an autosomal recessive disorder discovered
recently from an isolated region in Finland. The disorder is characterized by normal early
development, generalized tonic-clonic seizures with onset at 5-10 years of age, and progressive
mental retardation beginning 2-5 years after the onset of seizures. We recently mapped the EPMR
locus to a 7-cM region on chromosome 8p between markers AFM185xb2 and D8S262. A
recombination detected with a new microsatellite marker AFMa054td9 narrows the region to 4 cM.
A yeast artificial chromosome (YAC) contig containing 22 YACs was constructed across the
disease gene region. The YAC contig is characterized by a collection of 19 YAC-end sequence-tag
sites together with seven microsatellite markers. The entire YAC contig spans a minimum of 3 Mb.
Moreover, the distal end of the contig contains a subtelomeric YAC yRM2205 that anchors the
contig to the telomere. Construction of a YAC contig across the disease gene region is an essential
step toward the isolation of the EPMR gene.
