This family consists of two proteins, mesencephalic astrocyte-derived neurotrophic factor (MANF)5 and cerebral dopamine neurotrophic factor (CDNF).6 Both factors, when delivered into the extracellular space of the brain or applied via viral vectors potently antagonize neurological damage in the rodent models of Parkinson's disease. The gene discussed is CDNF; the disease is Parkinson disease.