Scientists find genes that make some kids’ hair uncombable | Science News for Students

Scientists find genes that make some kids’ hair uncombable

Mutations in any of three genes causes a disorder that makes hair impossibly tangled
Jan 18, 2017 — 7:10 am EST
so much hair

Think your hair is hard to comb? It’s a piece of cake compared to what a few kids confront every day. They’ve inherited a gene for uncombable hair.

hjalmeida / iStockphoto

Lots of kids have heard this refrain: “Brush your hair! It’s a mess!” For most people, combing hair may be, at most, a chore. For an unfortunate few kids, however, every day is a bad hair day. And they can’t help it. These youngsters have a strange — though usually not permanent — condition that makes their snarly hair nearly impossible to tame. Scientists have now pinpointed several genes that appear to be responsible for this “uncombable hair syndrome.”

Yes, that’s it’s official name.

Affected children have frizzy, tangled hair. The abnormality has nothing to do with grooming habits. The hair’s structure is simply different from that in most people. The bad news: Shampoos and conditioners rarely do much to control it.

Normally, a hair strand or shaft (the part of the hair that sticks out of the scalp) looks relatively smooth under a microscope. In kids with uncombable hair syndrome, the shaft instead appears to have grooves along each strand’s length. A cross-section of a single hair shaft (the shape you’d see if you were looking at it from the end) resembles a heart or a kidney. Still, the hair looks somewhat shiny. The good news: Most kids will outgrow this curse of totally unruly hair. By the time they reach their teens, their hair starts to sort itself out.

No one knows how common uncombable hair syndrome is, says Regina Betz. She is an author of the new study who works at the Institute of Human Genetics at the University of Bonn in Germany. Betz is an expert in rare hereditary hair disorders. To date, scientists have reported only about 100 cases worldwide. But there are probably many more, Betz says. "Maybe they didn't go to the doctor," she says. "Or the doctor did not recognize that this was uncombable hair syndrome." That’s not surprising, given how rare the condition is.

Scientists already knew that the syndrome was genetic. After all, if one kid has it, someone else in his or her family generally does too — or did. But no one had any clue about which gene might be to blame. That's because there had been so few studies on the condition.

tangled hair
In some kids — no amount of brushing will make it lie flat. A new study pinpoints three genes responsible for the frizz.
UNIVERSITY OF BONN

When one of Betz’s colleagues told her about a British family with two children having this uncombable hair, she got curious and decided to launch a study. Her team roped in more affected kids from across Europe. First, they analyzed each child’s DNA. That’s our genetic instruction book. They sequenced that DNA, meaning they used a tool to read out the exact order of the individual building blocks in this molecule.

Next the scientists compared those DNA sequences in children with uncombable hair syndrome to those in people whose hair behaves normally. Three genes differed in the kids with uncombable hair. Betz’s team shared published its findings online in the November 2016 American Journal of Human Genetics.

Scientists already knew that these three genes are responsible for making hair strong. They contribute to the structure of a hair’s shaft. But Betz and her colleagues found that if there is a mutation in one of the genes — a change in its DNA —  that's enough to make a child’s hair totally unmanageable.

To find out how the mutations messed with a kid’s hair, Betz’s team did an experiment. In the lab, they grew both normal cells and cells with the mutation. When they did that, they found that the mutations caused the strong-hair genes to make proteins that formed messy clumps. The normal form of the proteins won’t normally do that.

Next, the researchers wanted to find out whether mutations in those genes would lead to uncombable hair in real life. Of course, it would be unethical to mess with people’s genes to find out. Instead, the team used mice. They disabled one of the three suspect genes in some mice. They left the others’ genes alone. The haircoats of the genetically modified animals were not smooth. Unlike those of the normal mice, their coats were wavy. (That's more or less the mouse version of uncombable hair.)

Betz says the study one day could lead to genetic tests to diagnose uncombable hair syndrome. If doctors could confirm a child inherited the mutant gene, this could help parents who are concerned.

Drug companies might even use the new data to devise treatments. But Betz thinks they won't be interested just yet. Because the condition is so rare, there wouldn’t be many customers.

As a dermatologist, Shani Francis is an Illinois doctor who treats people with skin and hair diseases. She also teaches at the University of Chicago's Pritzker School of Medicine. The new study provides "exciting new information," she says, because no one had identified genes linked to uncombable hair syndrome before. Plus, the study may help scientists understand other abnormalities affecting hair’s structure. These include the common problem of split ends, when the end of hair strands split into two parts. The findings could even help researchers tackle a problem in which bumps appear along hair strands — a condition known as bamboo hair.

Power Words

(more about Power Words)

cell     The smallest structural and functional unit of an organism. Typically too small to see with the naked eye, it consists of watery fluid surrounded by a membrane or wall. Animals are made of anywhere from thousands to trillions of cells, depending on their size. Some organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.

colleague     Someone who works with another; a co-worker or team member.

dermatology       The branch of medicine concerned with skin disorders and their treatments. Doctors who treat these disorders are called dermatologists.

diagnose     To analyze clues or symptoms in the search for their cause. The conclusion usually results in a diagnosis — identification of the causal problem or disease.

disorder     (in medicine) A condition where the body does not work appropriately, leading to what might be viewed as an illness. This term can sometimes be used interchangeably with disease.

DNA     (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. It is built on a backbone of phosphorus, oxygen, and carbon atoms. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.

ethics       (adj. ethical ) A code of conduct for how people interact with others and their environment. To be ethical, people should treat others fairly, avoid cheating or dishonesty in any form and avoid taking or using more than their fair share of resources (which means, to avoid greed). Ethical behavior also would not put others at risk without alerting people to the dangers beforehand and having them choose to accept the potential risks.

gene     (adj. genetic) A segment of DNA that codes, or holds instructions, for producing a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.

heredity     A biological process by which genetic information is passed from parent to offspring. That information carries the genetic blueprints for a host of traits that can be passed along in whole or in part, from hair color and height to susceptibility to various diseases.

information     (as opposed to data) Facts provided or trends learned about something or someone, often as a result of studying data.

journal     (in science) A publication in which scientists share their research findings with the public. Some journals publish papers from all fields of science, technology, engineering and math, while others are specific to a single subject. The best journals are peer-reviewed: They send out all submitted articles to outside experts to be read and critiqued. The goal, here, is to prevent the publication of mistakes, fraud or sloppy work.

kidney     Each in a pair of organs in mammals that filters blood and produces urine.

microscope     An instrument used to view objects, like bacteria, or the single cells of plants or animals, that are too small to be visible to the unaided eye.

molecule       An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).

mutation     (v. mutate) Some change that occurs to a gene in an organism’s DNA. Some mutations occur naturally. Others can be triggered by outside factors, such as pollution, radiation, medicines or something in the diet. A gene with this change is referred to as a mutant.

online     A term that refers to things that can be found or done on the Internet.

protein     Compound made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. The hemoglobin in blood and the antibodies that attempt to fight infections are among the better-known, stand-alone proteins. Medicines frequently work by latching onto proteins.

sequencing     (in genetics) Technologies that determine the order of nucleotides or letters in a DNA molecule that spell out an organism’s traits.

syndrome     Two or more symptoms that together characterize a particular disease, disorder or social condition.

NGSS: 

  • MS-LS3-1
  • HS-LS1-1

Citation

Journal: F.B.Ü. Basmanav et al. Mutations in three genes encoding proteins involved in hair shaft formation cause uncombable hair syndrome. The American Journal of Human Genetics. December 1, 2016, Vol. 99, p. 1292. doi: 10.1016/j.ajhg.2016.10.004.