Getting to the core of repeat expansions by cell reprogramming

In this issue of Cell Stem Cell, Ku et?al. (2010) demonstrate that iPSCS derived from Friedreich's ataxia patients exhibit expansion of the causative (GAA)(n) repeat, consistent with the repeat instability observed during intergenerational transmissions in humans. Furthermore, the epigenetic signature of the disease remains intact in Friedreich's ataxia iPSCs.