Linkage studies of Friedreich ataxia by means of blood-group and protein markers.

Friedreich ataxia (FA) is an autosomal recessive, neuro-degenerative disorder in which the pathogenetic mechanism remains unidentified despite extensive biochemical studies. Genetic-linkage studies provide an alternative approach to determining the basic defect. Linkage analysis between FA and 36 polymorphic-blood-group and protein markers has been carried out on three separate patient populations--16 families from the inbred Acadian population of Louisiana, 21 French-Canadian families from Quebec, and nine apparently unrelated British families--in an attempt to determine the chromosomal location of the disease mutation. Neither evidence of linkage to any of the markers investigated nor heterogeneity among the populations was found for any of the comparisons. The negative lod scores exclude the locus for FA from greater than 20% of the genome.