Three closely related genes encoding amino acid transport proteins are clustered on 5q32 in humans, and Chromosome (Chr) 11 in mice. The human SLC36A1 gene, which encodes the lysosomal amino acid transporter LYAAT1/PAT1, generates multiple alternative mRNAs, some of which encode truncated proteins. SLC36A1 is expressed in numerous tissues, whereas expression of SLC36A2, which encodes the glycine transporter tramdorin1/PAT2, is most abundant in kidney and muscle. Expression of a third gene, SLC36A3, is restricted to testis. Mouse Slc36a2 also is expressed in bone and fat tissue. Polymorphisms in human SLC36A2 exclude it as a candidate locus for a peripheral neuropathy that has been mapped to 5q31-33. SLC36A2 is a candidate gene for 5q-myelodysplastic syndrome, on the basis of its chromosomal location and its expression in bone.