Health-related quality of life measures in genetic disorders: an outcome variable for consideration in clinical trials.

The field of medical genetics is rapidly advancing, and therapeutic options to treat genetic syndromes are becoming increasingly available. An understanding of the pathophysiology of various genetic disorders has provided researchers the opportunity to propose and test pharmacologic agents in preclinical murine models with hopes of translation to human trials. The development of clinical trials can be costly and time consuming, particularly for rare conditions. Pilot feasibility studies should be performed when designing clinical trials for genetic disorders. The development and selection of appropriate outcome measures are particularly paramount in the implementation of clinical trials. The selection of inappropriate outcome measures can lead to non-measurable differences or clinically insignificant findings. In addition, just as age appropriate measures are needed, some instruments may not apply to populations with specific genetic disorders that have significant cognitive and physical impairment, as the measures may not be sensitive enough to identify clinically significant changes. In the last decade, health-related quality of life measures (HRQOL) have been increasingly included as an outcome measure in clinical trials. While traditional clinical outcomes are important, these newly developed instruments should be considered along with clinical indicators as measures of effect in clinical trials of interventions in genetic disorders. 2009 Wiley-Liss, Inc.