Gene mutations affect everyone. They are caused by natural mistakes during replication, mutagens such as some chemicals or radiation, and some viruses. But most of the time, mutations don’t have a big effect on us and they go unnoticed. But it is not uncommon that you can have a disorder from a mutation. Mutations can have a wide range of severity and it all depends on the type and person. In a point mutation, the protein is usually still functional. Where else in a frameshift and chromosomal mutations, proteins or genes can be totally changed. These are more serious. Mutations don’t affect just humans, they also affect animals, plants, bacteria, protists, and fungi. The mutations I have researched are Down syndrome, Ehlers-Danlos syndrome, albinism in animals and Brachycephalic syndrome.
Down syndrome, also referred to as Trisomy 21, is the most common condition in the United States that has to do with chromosomes. Approximately 1 in 700 babies will be born with Down syndrome. This is about 6,000 every year. A person with Down syndrome has an extra full or partial chromosome 21. The typical human has 46 chromosomes while people with Down syndrome have 47. Down Syndrome is diagnosed at birth or even before. A prenatal screen, which includes a blood test and ultrasound, will tell you the chance that the fetus has Down syndrome. It is also diagnosed at birth. Doctors look for physical characteristics like low muscle tone, a flattened face, a palmar crease, a short neck, and small ears. If a baby has some of these features, a karyotype is done to confirm the diagnosis. People with Down syndrome can have hearing problems, eye diseases, sleep apnea and heart defects at birth. They also usually have an IQ in the lower range and cognitive delays. Although we know that Down syndrome is caused by an extra chromosome 21, we are still unsure why this occurs. We do know that expecting mothers over 35, have an increased risk of having a child with Down syndrome. The life expectancy for people with Down syndrome has increased tremendously. At one time the life expectancy was about 9 years and today it’s about 60 years or longer. Kids and adults with Down syndrome are just like everyone else. They like to hang out with friends and are loving to others.
Another mutation that affects humans is Ehlers-Danlos Syndrome (EDS). EDS is a disease that weakens tendons and ligaments in your body. These weakenings can cause skin and joints to spread farther than normal. Because of this, your joints are more likely to dislocate. Your body’s tissue is also very delicate causing bruising and tearing to happen fairly easily. Children who have this usually have a weaker muscle tone which slows down motor skills like walking and standing. Doctors are able to diagnose this through physical testing. They measure joint mobility, feel your skin and see how far it stretches. After diagnosing it, doctors are able to able to help treat it through physical therapy, braces or wheelchairs, vitamins and some over the counter drugs. It is not curable but these things may help. Mutations for EDS have been found on 19 genes. The severity is different for everyone. Some have worse types of EDS than others. Even with the broad range of severity, this doesn’t usually change your life expectancy. Depending on the version or type of EDS you have depends on how you pass it to your child. You can pass it through autosomal dominant, autosomal recessive and X-Linked recessive inheritance patterns. For autosomal dominant, if one parent gives the EDS gene and the other one doesn’t, there is a 50% chance the child with have EDS. For autosomal recessive, both parents must give the child an EDS gene. There is a 25% chance the child will have EDS and a 50% chance they will be a carrier of it. For X-linked recessive, if the mother carries the EDS gene, there is a 50% chance that a female could get it and a 50% chance for the male also. If the man carries the EDS gene, all daughters will be affected and none of the sons would be.
Animals can also experience mutations. One that isn’t usually helpful for animals is albinism. Albinism is when an animal is white instead of its normal color. This occurs when an animal has lack melanin, which is a dark pigment. A mutation happens on the TYR gene. That gene is responsible for making an enzyme called tyrosinase. This enzyme is located in melanocytes which produces melanin and gives the animal its color. Albino animals are characterized by being completely or partially white with pink or blue eyes. Being white, it makes it harder for the animal to blend into its surrounding. Predators can spot them making them easy prey. Albinism isn’t very common though. It is a recessive gene which makes it harder to get. It is even harder to be albino because very few animals even carry the recessive gene for it. Some examples of animals that have been seen with albinism are turtles, deer, frogs, raccoons, catfish, and snakes. There are specific locations that are known to have more albino animals than usual. An example is a town in Missouri called Marionville. The town has a greater population of white squirrels than normal squirrels. The people living their take care of the white squirrels and even have laws protecting them from hunters.
Lastly, a mutation called brachycephalic syndrome has a harmful effect on dogs. Dogs such as Pugs, Bulldogs, Shih Tzus, and Boxers commonly have brachycephalic syndrome. Most of there face looks “smooshed”. Their face and nose can look like they are being pushed in. The name of this describes exactly what it is. The prefix “brachy” means short and “cephalic” means head. Because of the anatomy of these dogs heads, they tend to have troubles breathing and have respiratory problems. Many times their nostrils and trachea are narrow making it hard to breathe. Some symptoms your dog might have is snorting, snoring, coughing or even fainting after exercise. Dogs are able to get treated for it. They can take oxygen therapy or even have surgery done to fix it. Researchers from the Roslin Institution at the University of Edinburgh have connected the short face structure to the SMOC2 gene. This is helpful for finding the molecular composition of the skull.
Mutations are very common among humans and animals. One little change in a DNA sequence can have a huge impact on the organism, or none at all. It all depends on the type of mutation and the results of the protein being made.
