In this study, we demonstrate that mitochondrial dysfunction is also a prominent feature of the lung in HPS and that HPS-2 mutations elicit a wide range of effects on this organelle, including altering bioenergetics and redox balance as well as affecting essential regulatory processes, such as the UPRmt and production of biogenesis factors. The gene discussed is AP3B1; the disease is Hermansky-Pudlak syndrome.