Fig 1. Instability analysis of the expanded GAAs in the FXN gene across different somatic tissues.

Genomic DNA was extracted from heart (H), cerebral cortex (Cc), spinal cord (Sc), cerebellar cortex (Cb) and pancreas (P) tissues and the GAA repeats in the FXN locus were amplified by PCR. The results from FRDA patients (A) F2 (B) F7 and (C) M6 shown as examples. (-) represents no-template control and (+) represents positive control for amplification of the expanded GAAs (genomic DNA isolated from fibroblasts obtained from an unrelated FRDA patient). (D-F) A GAA repeat tract at the 5q23 locus was amplified by PCR using the same genomic DNA templates used for reactions shown in (A-C). (G-I) A fragment spanning intron 1—exon 2 of the FXN gene, downstream of the GAA tract, was also amplified using the same templates to serve as a control for genomic DNA quality.