Fine-Mapping of the Spinal Muscular Atrophy Locus to a Region
Flanked by MAP1B and D5S6
L.M. Brzustowicz, P.W. Kleyn, F.M. Boyce, L.L. Lien,
A.P. Monaco, G.K. Penchaszadeh, K. Das, C.H. Wang, T.L. Munsat,
J. Ott, L.M. Kunkel, T.C. Gilliam
Genomics , 13(4), 991--998 (1992 Aug)
Abstract
The microtubule-associated protein 1B (MAP1B) locus has been mapped
in close proximity to spinal muscular atrophy (SMA) on chromosome
5q13. We have identified a second microsatellite within a MAP1B
intron, which increases the heterozygosity of this locus to 94%. Two
unambiguous recombination events establish MAP1B as a closely
linked, distal flanking marker for the disease locus, while a third
recombinant establishes D5S6 as the proximal flanking marker. The
combination of key recombinants and linkage analysis place the SMA
gene in an approximately 2-cM interval between loci D5S6 and MAP1B.
Physical mapping and cloning locate MAP1B within 250 kb of locus
D5S112. The identification and characterization of a highly
polymorphic gene locus tightly linked to SMA will facilitate
isolation of the disease gene, evaluation of heterogeneity, and
development of a prenatal test for SMA.
