Extraintestinal manifestations of celiac disease: 33-mer gliadin binding to glutamate receptor GRINA as a new explanation.

We propose a biochemical mechanism for celiac disease and non-celiac gluten sensitivity that may rationalize many of the extradigestive disorders not explained by the current immunogenetic model. Our hypothesis is based on the homology between the 33-mer gliadin peptide and a component of the NMDA glutamate receptor ion channel - the human GRINA protein - using BLASTP software. Based on this homology the 33-mer may act as a natural antagonist interfering with the normal interactions of GRINA and its partners. The theory is supported by numerous independent data from the literature, and provides a mechanistic link with otherwise unrelated disorders, such as cleft lip and palate, thyroid dysfunction, restless legs syndrome, depression, ataxia, hearing loss, fibromyalgia, dermatitis herpetiformis, schizophrenia, toxoplasmosis, anemia, osteopenia, Fabry disease, Barret's adenocarcinoma, neuroblastoma, urinary incontinence, recurrent miscarriage, cardiac anomalies, reduced risk of breast cancer, stiff person syndrome, etc. The hypothesis also anticipates better animal models, and has the potential to open new avenues of research.