Mediates the calcium-dependent uptake of imino acids such as L-proline, N-methyl-L-proline and pipecolate as well as N-methylated amino acids. Involved in the transport of glycine. Located in the apical brush border membrane of kidney proximal tubule cells. Kidney and small intestine. Expressed in the S3 segment of the proximal tubule. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Haploinsufficiency of SLC6A20 combined with deficiency of the neutral amino acid transporter SLC6A19 or partially inactivating mutations in SLC36A2, is responsible for iminoglycinuria. Additional polymorphisms and mutations in SLC6A18 can contribute to the IG phenotype in some families. Belongs to the sodium:neurotransmitter symporter (SNF) (TC 2.A.22) family. SLC6A20 subfamily.