Red Hair
Genetic Risk Factors

Author: Gianpiero Pescarmona
Date: 29/05/2018


Red hair (or ginger hair) occurs naturally in 1–2% of the human population. It occurs more frequently (2–6%) in people of northern or western European ancestry, and less frequently in other populations. Red hair appears most commonly in people with two copies of a recessive allele on chromosome 16 which produces an altered version of the MC1R protein.



MC1R Protein

The melanocortin 1 receptor, also known as melanocyte-stimulating hormone receptor (MSHR), melanin-activating peptide receptor, or melanotropin receptor, is a G protein–coupled receptor that binds to a class of pituitary peptide hormones known as the melanocortins, which include adrenocorticotropic hormone (ACTH) and the different forms of melanocyte-stimulating hormone (MSH).

MC1R is one of the key proteins involved in regulating mammalian skin and hair color. It is located on the plasma membrane of specialized cells known as melanocytes, which produce the pigment melanin through the process of melanogenesis. It works by controlling the type of melanin being produced, and its activation causes the melanocyte to switch from generating the yellow or red phaeomelanin by default to the brown or black eumelanin in replacement.

Agouti-signaling protein (ASIP_HUMAN)

ASIP is involved in the regulation of melanogenesis. The binding of ASP to MC1R precludes alpha-MSH initiated signaling and thus blocks production of cAMP, leading to a down-regulation of eumelanogenesis (brown/black pigment) and thus increasing synthesis of pheomelanin (yellow/red pigment). In higher primates, agouti may affect the quality of hair pigmentation rather than its pattern of deposition. Could well play a role in neuroendocrine aspects of melanocortin action. May have some functional role in regulating the lipid metabolism with adipocytes.

5,6-dihydroxyindole-2-carboxylic acid oxidase (TYRP1_HUMAN)

Catalyzes the oxidation of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) into indole-5,6-quinone-2-carboxylic acid in the presence of bound Cu2+ ions (PubMed:28661582). May regulate or influence the type of melanin synthesized (PubMed:22556244, PubMed:16704458). Also to a lower extent, capable of hydroxylating tyrosine and producing melanin

L-dopachrome tautomerase (DCT gene, TYRP2_HUMAN)

This protein is involved in the pathway melanin biosynthesis, which is part of Pigment biosynthesis.
View all proteins of this organism that are known to be involved in the pathway melanin biosynthesis and in Pigment biosynthesis.

External links not available on Wikipedia have to be added here




When relevant for the function

  • Primary structure
  • Secondary structure
  • Tertiary structure
  • Quaternary structure

Protein Aminoacids Percentage (Width 700 px)

Melanin Synthesis Proteins

Proopiomelanocortin + Melanin Synthesis


mRNA synthesis
protein synthesis

post-translational modifications


cellular localization,
biological function

  • Enzymes
BRENDA - The Comprehensive Enzyme Information System"URL":
KEGG Pathways"URL":
Human Metabolome Database"URL":
  • Cell signaling and Ligand transport
  • Structural proteins



2018-05-29T21:37:46 - Gianpiero Pescarmona

Impact of interrupted leptin pathways on ventilatory control. 1985

Agouti yellow mice, with blocked melanocortin pathways, exhibited a significant depression of the hypercapnic sensitivity compared with weight-matched wild-type controls during non-rapid eye movement sleep (5.8 +/- 0.7 vs. 8.9 +/- 0.7 ml x min(-1) x %CO(-1), P < 0.01), but not during wakefulness.


Cyclosporine A affects open field behavior in DA rats. 1998

However, treatment with CsA induces neuropsychological complications in patients, including affective disorders such as anxiety, disorientation, depression, aggression, paranoia, and apathy.
"CsA and DHT":

AddThis Social Bookmark Button