Is HLA-DQ2 useful for sleep?

Based on the provided context, there is no evidence that HLA-DQ2 is useful for assessing sleep. HLA-DQ2 is a genetic marker primarily associated with celiac disease and gluten sensitivity. The context only mentions HLA-DQ in relation to gluten intolerance testing, not sleep. No studies or data in the context link HLA-DQ2 to sleep quality, duration, or disorders. While untreated celiac disease can cause symptoms like fatigue or insomnia via inflammation or malabsorption, this is an indirect and speculative connection not supported by the given sources. Consumer DNA tests often overclaim the significance of such markers. Therefore, the evidence is rated as unclear. For sleep issues, established factors such as sleep hygiene, stress, and medical conditions (e.g., sleep apnea) are far more relevant. HLA-DQ2 testing is not a valid tool for sleep assessment.