CAG EXPANSIONS IN A NOVEL GENE FOR MACHADO-JOSEPH DISEASE AT CHROMOSOME 14Q32.1

We have identified a novel gene containing CAG repeats and mapped it t o chromosome 14q32.1, the genetic locus for Machado-Joseph disease (MJ D). In normal individuals the gene contains between 13 and 36 CAG repe ats, whereas most of the clinically diagnosed patients and all of the affected members of a family with the clinical and pathological diagno sis of MJD show expansion of the repeat-number (from 68-79). Southern blot analyses and genomic cloning demonstrates the existence of relate d genes. These results raise the possibility that similar abnormalitie s in related genes may give rise to diseases similar to MJD.