of protein metabolites, namely ammonia. as of 2013, in the u.s., the incidence of urea cycle disorders has been estimated to be 1 case in every 31,000 births, resulting in about 113 new cases annually. special populations neonates protein toxicity, specifically ammonia buildup, can affect preterm newborns that have serious defects in the urea cycle enzymes with almost no physical manifestations at birth. clinical symptoms can manifest within a few days of birth, causing extreme illness and intellectual disability or death, if left untreated. hyperammonemia in newborns can be diagnosed with visual cues like sepsis-like presentation, hyperventilation, fluctuating body temperature, and respiratory distress; blood panels can also be used to form differential diagnoses between hyperammonemia caused by urea cycle disorders and other disorders. neurodegenerative diseases people who have neurodegenerative diseases like huntington's disease, dementia, parkinson's disease, and amyotrophic lateral sclerosis (als), also often show symptoms of protein toxicity. cellular deficits and genetic mutations caused by these neurodegenerative diseases can pathologically alter gene transcription, negatively affecting protein metabolism.