However, our findings have shown increased levels of GNPDA2 not only in AD patients but also in a wide variety of neurodegenerative disorders such as Lewy body dementia, progressive supranuclear palsy, mixed dementia and amyotrophic lateral sclerosis, strongly suggesting GNPDA2 as another source of excessive ammonia. The gene discussed is GNPDA2; the disease is progressive supranuclear palsy.