PKU is a rare autosomal recessive condition associated with disruption in dopamine synthesis. Although early diagnosis and treatment prevent the severe impairments associated with untreated PKU, individuals with early-treated PKU (ETPKU) nonetheless experience significant sequelae, including impaired working memory and increased risk for anxiety problems. Past research with other clinical populations (e.g., generalized anxiety disorder) suggests that the two phenomena may be linked, with increased anxiety contributing to poorer WM performance. Currently we propose to initiate an exciting new line of research examining the potential relationship between anxiety and WM in ETPKU. The proposed study will also apply remote neuropsychological performance-based assessment to the study of ETPKU and thus overcoming the geographical limitations/challenges associated with recruitment of participants with this rare disease.

Inclusion Criteria:

• Participants with PKU will be included if they were diagnosed as newborns and immediately started on treatment.

Exclusion Criteria:

• Individuals with a history of neurologic compromise or major medical disorder unrelated to PKU (e.g., closed head injury, diabetes, multiple sclerosis) will be excluded. In addition, individuals with PKU will be excluded if they are on a medication called Peg-Valiant/ PEG-PAL/ Pegvaliase/Palynziq.

Individuals age 18-40 years old with and without PKU

To be determined