Screening of a human hippocampal cDNA library with a rat creatine transporter cDNA-specific probe revealed two types of clones, One identical to the published creatine transporter cDNA sequence (CRT1) and another (CRT2) with four segments of oligodeoxyribonucleotide substitution or addition in different sites of the CRT1 coding sequence, Translation of the CRT2 coding sequence reveals a new protein with regions of perfect homology with the CRT1 amino-acid sequence.