Evidence check: tTG IgA in the context of Schlaf

The query asks about tTG IgA (tissue transglutaminase IgA) in the context of sleep. The provided context contains no information on this biomarker or sleep. In general medicine, tTG IgA is the primary serological marker for celiac disease. There is some evidence that untreated celiac disease may impair sleep via inflammation, nutrient deficiencies (e.g., iron, vitamin D), or comorbid conditions (e.g., restless legs syndrome). However, the evidence is mostly mechanistic or from observational studies; robust randomized trials are lacking. A standalone tTG IgA test without confirmed celiac diagnosis is not informative for sleep issues. Caveat: If celiac disease is suspected, proper medical evaluation including duodenal biopsy is necessary; a gluten-free diet should not be started without a confirmed diagnosis.