An observant and curious student asked me today, “Why do some kids have freckles and others don’t?” Freckles, those little brown specks found on a child’s cheeks and nose, are caused by a combination of genetics and the sun.
According to Stanford University, freckles, which usually appear on fair-skinned people, contain melanin. Melanin is a pigment protein found in our skin. This chemical protects the skin by shielding it from the sun’s ultraviolet rays. Some people tan easily because their melanin-producing cells, known as melanocytes, are spread evenly across their skin.
However, kids with light skin and eye-color have less melanin and melanocytes that are clumped together. So, the clusters of cells that make pigment when exposed to the sun show up as freckles and the surrounding skin is easily sunburned.
Naturally, my student’s next question was, “Why do some people have clumps of melanocytes while others don’t?”
The answer is the MC1R gene that regulates skin pigment. Some people are born with an MC1R gene that causes red hair and freckles or just freckles. In a sense, freckles appear on kids who have a skin pigment gene which is broken or not functioning properly.
Parents may notice that their child’s freckles fade away during the darker winter days and return each summer. Also, sun exposure increases freckling and freckle-faced kids are more likely to sunburn. Freckles are a good reminder that all children, freckled and nonfreckled, should wear sunscreen to protect their skin from sunburn and the harmful rays of the sun.
Sources:
Stanford School of Medicine. Why Do I Have Freckles? Web. 29, Feb. 2012.
http://www.thetech.org/genetics/ask.php?id=195
KidsHealth. What Are Freckles? Web. 29, Feb. 2012.
http://kidshealth.org/kid/talk/qa/freckles.html#cat20248
Reviewed March 1, 2012
by Michele Blacksberg RN
Edited by Jody Smith