Linkage analysis in autosomal recessive limb-girdle muscular dystrophy (AR LGMD) maps a sixth form to 5q33-34 (LGMD2F) and indicates that there is at least one more subtype of AR LGMD.
Limb-girdle muscular dystrophies (LGMDs) represent a clinically heterogeneous group of genetic diseases characterised by progressive weakness of the pelvic and shoulder girdle muscles. An autosomal dominant form (LGMD1A) has been mapped at 5q22.3-31.3, while five genes responsible for the autosomal recessive forms were mapped respectively at: 15q15.1 (LGMD2A), 2p12-p16 (LGMD2B), 13q12 (LGMD2C), 17q12-q21.33 (LGMD2D) and 4q12 (LGMD2E). Among 17 autosomal recessive (AR) LGMD Brazilian families with at least three affected sibs, we were able to exclude four families (one mild and three severe) from all these five known loci as well as from the dystroglycan and syntrophin genes. Therefore, we have performed a genome-wide search in two of the severely affected families, which are alpha-sarcoglycan negative. We demonstrate linkage of these two Duchenne muscular dystrophy-like families to 5q33-34, and propose to classify them as LGMD2F. In addition, linkage analysis in the other two genealogies that are alpha-sarcoglycan positive suggests that there is at least one other gene which causes AR LGMD.
Passos-Bueno
M R
MR
Departamento de Biologia, Instituto de Biociências, São Paulo, Brazil.
Moreira
E S
ES
Vainzof
M
M
Marie
S K
SK
Zatz
M
M
D002874:Chromosome Mapping; D002895:Chromosomes, Human, Pair 5; D005260:Female; D005808:Genes, Recessive; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D008297:Male; D009136:Muscular Dystrophies / Q000145:classification / Q000235:genetics*; D010375:Pedigree
D005819:Genetic Markers