High-Resolution Genetic Map aroundtheSpinalMuscular Atrophy(SMA)Locuson Chromosome5

Summary Although autosomal recessive spinal muscular atrophy (SMA)hasbeenmappedto chromosome5ql2-ql3, there isforthis region no genetic map based on highly informative markers. Inthis study we present the mapping oftwo previously reported microsatellite markers in40CEPH and31SMA pedigrees. We also describe theisolation ofa new microsatellite marker attheD5S112locus. Themost likely orderofmarkers (with recombination fractions given inparentheses) isScen-D5S6-(.02)-D5S125-(.04)-(JK53CA1/ 2,D5S112)-(.04)-D5S39-qter. Therelative order ofD5S6,D5S112,andD5S39was confirmed byinsitu hybridization. Multipoint linkage analysis in31SMA families indicates thattheSMA locuslies inthe6-cM interval between D5S6andJK53CA1/2, D5S112.