Figure 4: Quantitative PCR assessment of TBK1 gene dose. The number of copies of the TBK1 gene was assessed in genomic DNA collected from white blood cells (A) and from iPSC-derived retinal ganglion cells (B) from an NTG patient from family 441 (Figure 1, III-1) and from control subject lymphocytes. This experiment confirms that the iPSC-derived cells carry the TBK1-gene duplication originally detected in lymphocytes.