The questionnaire is intended to be particularly applicable in clinical trials, with a focus on the impact of short stature and the physical functionality of those affected. The instrument will be further developed according to the Guidelines for PRO instrument development. It should be practical in its application and interpretation and applicable in the international context.~In addition, it will be investigated whether, from the parents' point of view, other instruments are suitable for measuring the quality of life of their short statured children. Their preference regarding the instruments will be assessed so that a recommendation can be made as to which instruments are particularly suitable.~A systematic literature review will be conducted to identify suitable instruments to measure the quality of life of short statured children aged 0 to 4.~Approximately 10-20 parents of 0-4 year old children with ACH, GHD and SGA will be recruited for the qualitative data collection (n = 30 to 60). The patients will be recruited through the BKMF (German Association for People of Short Stature and their Families).~In order to test the psychometric properties of the instruments, approximately 30 parents (15 mothers / 15 fathers) of 0-4 year old children with ACH, GHD and SGA will be recruited for the quantitative part of the study (n = 90). All participants will be asked to complete the QoLISSY or other instruments found suitable in the pilot test. For the purpose of cross-validation, the PEDSQL will be used in parallel.~Two weeks after receiving the field test, the re-test will be sent to ensure the reliability of the study. The re-test will be administered to a minimum of 20% of the participants.
The aim of the study is the adaption, implementation and validation of the instrument for the investigation of the short stature specific quality of life (QoLISSY) for children (age 0-4 years) with achondroplasia (ACH), Small for Gestational Age (SGA) and Growth Hormone Deficiency (GHD) from a parental perspective.