Maple Syrup Urine Disease (MSUD) is an autosomal recessive condition with an incidence of 1 in 185,000 births worldwide. Regardless of the type of MSUD, treatment includes immediate and lifelong dietary restriction of isoleucine, leucine and valine. There is little known about the psychosocial impact of MSUD on the developmental milestones of emerging adulthood. We used a qualitative case study approach to explore the human experiences of MSUD on young adults (n = 8) and parents (n = 8). All participants were administered a semi-structured, qualitative interview as well as quantitative measures. Six core themes emerged: 1) lifelong strain of dietary management; 2) social isolation from peers and impact on dating; 3) impact of MSUD on academics and employment; 4) medical experiences and transition to adult care; 5) impact on family functioning; and 6) positive effects and growth. The results of this investigation highlight and expand awareness of the psychological and social needs of young adults with MSUD. This study calls for a collaborative, multidisciplinary effort in the treatment of these patients and their families.