MC1R is the gene encoding the receptor for melanocyte stimulating hormone (MSH), one of two pigmentation related hormones encoded by the POMC gene. The MC1R receptor is variously known as the melanocortin 1 receptor, the melanocyte-stimulating hormone receptor, or the melanotropin receptor.
SNPs in MC1R have primarily been linked to light (or red) hair, fair skin, freckling, and perhaps not surprisingly, varying risk for both melanoma and non-melanoma skin cancers. For example, in one study of a type of melanoma in an Italian population, individuals having any type of MC1R variant were at 3 fold higher risk than individuals with wild-type MC1R genes. [PMID 16809487]
SNPs in MC1R also influence responses to opioid analgesic drugs used to treat pain. Drugs such as pentazocine (a kappa-type opioid agonist) appear to be most effective in redheaded and light skinned females who have less active MC1R protein activity. [PMID 12663858]
MC1R SNPs include:
- rs1805009, known as Asp294His or D294H; the most common variant associated with red hair and poor tanning ability in one study [PMID 7581459]
- rs1805006, known as Asp84Glu or D84E; appears to be associated with higher risk of melanoma [PMID 8894704]
- rs1805007, known as Arg151Cys or R151C; associated with red hair, and in redheaded females, linked to being more responsive to the anesthetics pentazocine, nalbuphine, and butorphanol, often used by dentists [PMID 9571181, PMID 12663858]
- rs1805008, known as Arg160Trp or R160W; associated with red hair in an Irish population [PMID 9665397]
These two are notable for not increasing the risk of melanoma [PMID 18366057]
- rs2228479, known as Val92Met or V92M; also commonly associated with red (or blond) hair and poor tanning, but note high presence in one Asian population [PMID 7581459, PMID 16463023].
- rs1805005, known as Val60Leu or V60L; associated with light blond hair in one study [PMID 9302268]