Genetic Homogeneity Between Acute and Chronic Forms of Spinal
Muscular Atrophy
T.C. Gilliam, L.M. Brzustowicz, L.H. Castilla,
T. Lehner, G.K. Penchaszadeh, R.J. Daniels,
B.C. Byth, J. Knowles, J.E. Hislop, Y. Shapira, V.
Dubowitz, T.L. Munsat, J. Ott, K.E. Davies
Nature , 345(6278), 823--825 (1990 Jun 28)
Abstract
The childhood-onset spinal muscular atrophies (SMAs) describe a
heterogeneous group of disorders that selectively affect the alpha
motoneuron. We have shown that chronic childhood-onset SMA (SMA II
and III) maps to a single locus on chromosome 5q. Acute SMA (SMA
Type I/Werdnig-Hoffmann/severe/infantile) is the main cause of
heritable infant mortality. Mapping the acute SMA locus by
conventional methods is complicated by the rapidly fatal course of
the disease and its recessive mode of inheritance. We present here
the typing of four inbred acute-SMA families with DNA markers on
chromosome 5q and analysis of these together with acute families
from our previous study to demonstrate genetic homogeneity between
the acute and chronic forms of SMA. The data indicate that the acute
SMA locus maps to chromosome 5q11.2-13.3. Two families seem unlinked
to 5q markers, raising the possibility of genetic heterogeneity or
disease misclassification within the acute and chronic family sets.
