Strikingly, ATP6AP2 and LAMP2, which are involved in lysosomal acidification and lysosomal protein degradation [24, 48], were significantly downregulated in NHD brains compared to controls (p = 1.44 × 10–4 and p = 5.95 × 10–3, respectively) (Fig. 6b and c). Here, ATP6AP2 is linked to Nasu-Hakola disease.