Whereas Hcy elevation and CBS inhibition in conditions associated with nutritional B6 deficiency or PLP-responsive CBS variants can be reversed by pyridoxine supplementation, the same may not be true for the functional B6 deficiency in AIP, as suggested by the failure of pyridoxine to reverse the increases in urinary Kyn metabolites [84]. The gene discussed is CBS; the disease is autoimmune pancreatitis.