How are tTG IgA and Müdigkeit related?

tTG IgA (tissue transglutaminase antibodies) is a key serological marker for celiac disease. Elevated levels indicate an immune response to gluten, leading to damage of the small intestinal lining. Fatigue is a common extra-intestinal symptom of celiac disease, potentially caused by iron deficiency anemia, malabsorption of nutrients (e.g., vitamin B12, folate, vitamin D), chronic inflammation, or associated autoimmune conditions like Hashimoto's thyroiditis. However, fatigue is non-specific and can have many causes. An isolated elevated tTG IgA without confirmatory small bowel biopsy is not diagnostic for celiac disease. False positives can occur, e.g., in other autoimmune diseases or infections. The evidence linking celiac disease and fatigue comes from observational studies and clinical experience. If you have persistent fatigue and elevated tTG IgA, a gastroenterological workup is recommended. A gluten-free diet often improves fatigue in confirmed celiac disease, but not in all individuals. Caveat: This information is based on general medical knowledge, not on specific sources from the provided context.