This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Gene for folate carrier protein located on ? 
Select and explain. 
A. Chromosome 10, B. Chromosome 5, C. Chromosome 21, D. Chromosome 9
C: Chromosome 21
Answer: C: Chromosome 21 
Explanation: Chromosome 21 [Ref: www.ihop netorgiunipub/ihopigi92248.htmll Transpo of folate compounds Folk acid transpo * Chromosome location ----> 21 q 223. * Gene name --> SLCI9AI solute carrier family 19 (folate transpoer), member * Gene product/function --> Transpoer for the iniake of folate. Transpo of folate occurs by novel mechanism called potocytosis which functionally couples three components namely the folate receptor, the folate transpoer and v-type h+ pump. * Alleles _> A 80G single nucleotide polymorphism