However, disruptions in heme homeostasis—due to mutations in heme transporters such as FLVCR1 or impaired heme–regulatory protein interactions—can result in neurodegenerative diseases, including Posterior Column Ataxia and Retinitis Pigmentosa (PCARP), Alzheimer’s disease, and Parkinson’s disease. The gene discussed is FLVCR1; the disease is early-onset autosomal dominant Alzheimer disease.