PIP4K2B and Huntington disease: (A) Reduction of mHtt protein levels in an HD patient fibroblast cell line (Q68) following exposure for 12 hr to NCT-504 (5 μM) (B) mHtt protein levels in patient fibroblast cell line (Q68) were analyzed following siRNA-mediated silencing of PIP4K2A, PIP4K2B and PIP4K2C genes.