Modulation of age at onset in Huntington's disease and spinocerebellar ataxia type 2 patients originated from eastern India

To identify the genetic modifier(s) that might alter the age at onset in Huntington's disease (HD) we have analyzed variations in GluR6 kainate receptor (GluR6), CA 150 gene, Delta2642 and polymorphic CCG repeat variation in huntingtin (htt) gene in 77 HD patients and normal individuals. In addition, variation in the RAII gene was analyzed in 30 spinocerebellar ataxia (SCA2) patients and normal individuals to show the possible influence on the age at onset. Multiple regression analysis indicated that variation in GluR6 and CCG repeat genotype might explain 6.2% and 3.1%, respectively, of the variability in the age at onset in HD. Similar analysis with SCA2 patients indicated that RAII might explain about 13% of the variability in the age at onset. Specific alleles in GluR6 and CA150 locus were only observed in HD patients. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.