Trx1 is a highly conserved 12-kDa protein, whose functional impairment has been implicated in a wide range of neurological and non-neurological disorders, including Alzheimer's disease, Parkinson's disease, diabetes, chronic obstructive pulmonary disease (COPD), and age-related macular degeneration (AMD). Here, SPRR2A is linked to chronic obstructive pulmonary disease.