Scientists Discover How Genetic Variation Affects Freckles Skip to content

Scientists Discover How Genetic Variation Affects Freckles

By Iceland Review

An international group of scientists led by Eiríkur Steingrímsson, professor at the University of Iceland’s Faculty of Medicine published an article in Cell which explains how genetic variation in a regulatory region affects human pigmentation and the formation of freckles.

decode-lab-large_psPhoto: Páll Stefánsson/Iceland Review.

The research has been ongoing since 2007 when scientists from deCODE genetics discovered a variation in a gene which influences hair and eye color and causes freckles, according to hi.is. Around the same time Steingrímsson’s research team revealed that this gene is under the influence of the melanocyte master regulator MITF, a key protein in the development of this cell type, but the effects of IRF4 on human pigmentation were unknown.

In collaboration with deCODE and others, Steingrímsson and his team has now demonstrated that the variation in IRF4-gene affects IRF4 expression in melanocytes leading to reduced production of the enzyme Tyrosinase, the enzyme that catalyzes the synthesis of the pigment melanin. This in turn causes individuals that carry the variation to have brown hair, blue eyes, freckles and skin that is sensitive to sunlight. This phenotype has been called the Irish phenotype as it is most common in Ireland, but is also found in Iceland and the rest of Europe.

ZR

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