TTC7A and immunodeficiency disease: TTC7 can stabilize the PI4KIIIα complex, and mutations in TTC7A, a TTC7 homolog, have been associated with a rare hereditary human disease, combined immunodeficiency with multiple intestinal atresia (CID-MIA) (OMIM: 609332), also known as gastrointestinal defects and immunodeficiency syndrome (GIDID).