The CaSR gene (chr 3q13.3-21) spans 103 kb and encodes the CaSR protein of 1078 amino acids. Exons are shown as either unfilled boxes (untranslated regions (UTR)), or filled boxes (protein coding regions). Exons 1a and 1b encode alternative 5'-UTRs. Exons 2-7 encode the CaSR protein. Exon 2 encodes the translation start codon (ATG) and the NH2-terminal part of the CaSR. Exon 7 encodes the stop codon (TAA) and the COOH-terminal part of the CaSR. rs7652589 (G > A, position 123371778) is located ~11000 bp upstream of P1 in the 5'-flanking region of the CASR gene. rs1501899 (G > A, position 123390018) is located 4668 bp downstream of P2 within intron 1 of the CASR gene.