Intergenerational instability is predictive of somatic instability.

(A) Repeat-length normalised levels of somatic mosaicism in the brains of SCA1 and MJD patients is similar to the levels of germ line instability observed in these disorders. Data were obtained from meta-analysis of a published study of somatic mosaicism in the cerebral cortex (N_MJD = 11, N_SCA1 = 7) and white matter (N_MJD = 9, N_SCA1 = 6) of SCA1 and MJD individuals (Table S1) (Maciel et al, 1997). (B) Repeat-length normalised levels of somatic mosaicism in buccal cells of HD and SCA7 patients is similar to the levels of germ line instability observed in these disorders. Data were obtained from meta-analysis of published studies of somatic mosaicism in the buccal cells of HD (N = 12) [8] and SCA7 (N = 1) [34] individuals (Table S2).