<s>[INST] <<SYS>> This is a medical question of type : frequency <</SYS>> How many people are affected by pyruvate carboxylase deficiency ? [/INST] Pyruvate carboxylase deficiency is a rare condition, with an estimated incidence of 1 in 250,000 births worldwide. This disorder appears to be much more common in some Algonkian Indian tribes in eastern Canada. </s>