The 3′-UTR deletion elevates PMP22 transcript levels. (A) For skin biopsy samples from controls (n = 16), HNPP (n = 1) and CMT1A patients (n = 15) and the proband (from two duplicate skin biopsies) in this study, purified RNA was submitted for Nanostring transcript quantitation analysis. The box and whisker plot shows PMP22 transcript values for the samples after normalization to Schwann cell-specific genes. (B) The graph shows normalized reporter activity from luciferase plasmids containing the human PMP22 3′-UTR or a version in which the neuropathy-associated deletion was introduced (3′-UTR del). The transfections were performed in the RT4 Schwann cell and Oli-neu oligodendrocyte cell lines. Error bars indicate standard deviations. (C) The two reporter plasmids were transfected with a control siRNA or a miR-29a mimic in RT4 cells, and resulting luciferase activities indicate that deletion of the 3′-UTR renders the luciferase reporter resistant to miR-29a repression. Reduction of luciferase activity by miR-29a co-transfection was significant (P < 0.02, t-test, n = 3) for the wild-type construct. HNNP = hereditary neuropathy with liability to pressure palsies.