- GAA instability in Friedreich's Ataxia shares a common, DNA-directed and intraallelic mechanism with other trinucleotide diseases. Gacy, A.M., Goellner, G.M., Spiro, C., Chen, X., Gupta, G., Bradbury, E.M., Dyer, R.B., Mikesell, M.J., Yao, J.Z., Johnson, A.J., Richter, A., Melançon, S.B., McMurray, C.T. Mol. Cell (1998)