Based on the information provided, it is unlikely that sapropterin alone can manage all PKU (Phenylketonuria) symptoms effectively. PKU is a genetic disorder characterized by the body's inability to break down an amino acid called phenylalanine, leading to its buildup in the body, which can cause intellectual disability and other health problems [1].

Sapropterin, also known as tetrahydrobiopterin, is a medication used to reduce phenylalanine levels in the blood of people with PKU [2]. However, it is not a cure for PKU and its effectiveness varies among individuals [1]. A study published in the Journal of Inherited Metabolic Disease found that sapropterin treatment led to a significant decrease in phenylalanine levels in only about half of the PKU patients studied [3].

Moreover, PKU management typically requires a combination of treatments, including a phenylalanine-restricted diet, supplements, and regular medical monitoring [1]. Therefore, while sapropterin can be an effective part of PKU treatment, it is not sufficient on its own to manage all PKU symptoms.

Sources:
[1] National Institutes of Health. Phenylketonuria. <https://medlineplus.gov/genetics/condition/phenylketonuria/>
[2] U.S. Food and Drug Administration. KUVAN (sapropterin dihydrochloride) tablets, for oral use. <https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/kuvan-sapropterin-dihydrochloride-tablets-oral-use>
[3] Journal of Inherited Metabolic Disease. Sapropterin response in phenylketonuria: a systematic review and individual patient data meta-analysis. <https://onlinelibrary.wiley.com/doi/full/10.1002/jimd.12165>
[4] DrugPatentWatch. Sapropterin. <https://www.drugpatentwatch.com/drugs/sapropterin>