Transcobalamin Ii Deficiency, also known as tcn2 deficiency, is related to pancytopenia and macrocytic anemia, and has symptoms including diarrhea, lethargy and vomiting. An important gene associated with Transcobalamin Ii Deficiency is TCN2 (Transcobalamin 2), and among its related pathways/superpathways are Infectious disease and Metabolism. Affiliated tissues include bone marrow and bone, and related phenotypes are abnormality of chromosome stability and methylmalonic aciduria