Can low mch and mchc only caused by iron deficiency or can there be any other reasons behind it , e.g. vitamin deficiency?

Low MCHC: aa30, MCHC being low is caused overwhelmingly by low iron and thus hemoglobin molecules per cell, however extremely rare hemoglobin mutations in predominately the alpha chain of hemoglobin protein which weakens the affinity for the Fe (iron) molecule to O2 can also cause low MCHC. We call these low affinity hemoglobinopathies and alpha chain thalassemias. Dr Hilliard