TREM2 and Nasu-Hakola disease: TREM2 mRNA levels were previously found to be reduced in patients with NHD caused by TREM2 variants (Chouery et al., 2008, Sasaki et al., 2015), and we found this to be the case for T66Mhom and W50Chom but not for T66Mhet iPSC-MGLCs.