The disease pernious anaemia is caused by the deficiency of vitamin

Pernicious anaemia is a condition brought on by a vitamin ${\mathrm{B}}_{12}$ deficiency.

When you have pernicious anaemia, your body is unable to absorb vitamin ${\mathrm{B}}_{12}$. This is due to the absence of intrinsic factor, a stomach-produced protein.

A deficit in this protein causes a shortage of vitamin ${\mathrm{B}}_{12}$. The patient receives injections of vitamin ${\mathrm{B}}_{12}$ to correct this deficit.