The Melanocortin-1 Receptor (MC1R) is a G-protein coupled receptor, which is 
responsible for production of the darker eumelanin pigment and the tanning 
response. The MC1R gene has many polymorphisms, some of which have been linked 
to variation in pigmentation phenotypes within human populations. In particular, 
the p.D84E, p.R151C, p.R160W and p.D294 H alleles have been strongly associated 
with red hair, fair skin and increased skin cancer risk. These red hair colour 
(RHC) variants are relatively well described and are thought to result in 
altered receptor function, while still retaining varying levels of signaling 
ability in vitro. The mouse Mc1r null phenotype is yellow fur colour, the 
p.R151C, p.R160W and p.D294 H alleles were able to partially rescue this 
phenotype, leading to the question of what the true null phenotype of MC1R would 
be in humans. Due to the rarity of MC1R null alleles in human populations, they 
have only been found in the heterozygous state until now. We report here the 
first case of a homozygous MC1R null individual, phenotypic analysis indicates 
that red hair and fair skin is found in the absence of MC1R function.