Transcobalamin II Deficiency Can Present without Hematological Manifestations: A Novel TCN2 Gene Variant

Transcobalamin II (TC) deficiency is a rare but serious metabolic disorder. It usually presents in the first year of life with failure to thrive, megaloblastic anemia and pancytopenia. Other features includes hypotonia, ataxia, lethargy, vomiting, diarrhea, mucosal ulceration, recurrent infections, agammaglobulinemia, methylmalonic aciduria and in rare cases, seizures. Besides, clinical presentation of TC deficiency may not be obvious thus leading to complex issues around diagnosis and treatment. Herein, we present TC II deficiency diagnosed in a 14 months old boy who presented with progressive myoclonic seizure, ataxia, truncal hypotonia, without any hematological manifestations and found to have a novel variant in the TCN2 gene.