Difficulties in Daily Life and Associated Factors, and QoL of Children with Inherited Metabolic Disease and Their Parents in Japan: A Literature Review.

To assess the quality of life (QoL) of children in Japan with inborn errors of metabolism (IEM) as well as of their parents, we reviewed 23 previous studies published in Japanese and 1 published in English, focusing on the difficulties they encounter in daily life, the factors associated with these difficulties, and their QoL. We divided the difficulties and associated factors into three developmental stages. At the infant stage, individuals with IEM tend to be at high risk of hypercatabolism. Their parents suffered anxiety and distress because of the child's diet therapy and regarded the parents' support group as an essential presence, particularly given that IEM is a rare disease. At the school-age stage, as their sphere of social relationships expanded, children with IEM became nervous about being compared with healthy children of their own age because of their diet therapy. At the adolescence-to-adulthood stage, the children suffered medically, economically, and socially. Even in the absence of any IEM symptoms, the children's QoL was affected by the demands associated with the metabolic disorder, such as diet and treatment. The psychological health of their caregivers was also poor. To improve the QoL of children with IEM and of their parents, future comprehensive quantitative and qualitative studies of their QoL and of their subjective support needs are required. Additionally, the specific factors related to the QoL of such individuals need to be explored in large population-based statistical studies.