Similar direction changes in biogenesis factors were also observed in the lung of HPS-2 mice, including the transcription regulators Pgc1α, Pgc1β, Prc, Nrf1 and Tfam (Figs. 6d) and the quantity of mtDNA (Fig. 6e). This evidence concerns the gene PPARGC1B and Hermansky-Pudlak syndrome 2.