Orphan (rare) diseases include congenital or acquired diseases, the frequency of occurrence of which does not exceed a certain number established by the laws of various countries. Despite its rarity, the orphan diseases make a significant contribution to the structure of population disability and most of them have no specific treatment. One of the main clinical challenges in these patients is to ensure their high quality of life (QOL). The review describes basic non-specific and specific questionnaires for assessing QOL in children with orphan diseases. An ideal questionnaire for assessing QOL in children with orphan disease should be sufficiently reliable, valid, sensitive and specific, fill out by a child or adolescents on their own, include questions covering as much as possible all areas of life and health aspects - especially those associated with the main decease. The questionnaire should not be too huge and complicated for the patient. From the side of the researcher, the simplicity of the tool in calculating and the ability to use the results for subsequent analysis are important.
Keywords: mental health; orphan diseases; personalized medicine; physical health; quality of life; rare diseases.