These 13 Genetic Abnormalities Make You More Vulnerable To Certain Disorders

The BRCA gene is an inherited mutation that dramatically increases one's likelihood of developing breast and ovarian cancer. For example, 72% of women who inherit a BRCA1 mutation and 69% of women who inherit a BRCA2 mutation will develop breast cancer before the age of 80, as opposed to the 12% risk in the general population. These mutations can also cause an increased risk of fallopian tube cancer, peritoneal cancer, acute myeloid leukemia, pancreatic cancer, and prostate cancer in men.

Because breast cancer is the most common result, some people who test positive for BRCA gene mutations, or who have a strong family history of breast cancer, may elect to get preventative mastectomies - the surgical removal of all breast tissue that could possibly become cancerous. It is still possible to get breast cancer after a mastectomy, but the chances decrease significantly. That said, breast cancer is not the only kind of cancer which the gene can cause, so mastectomy as prevention doesn't always work.

Cystic fibrosis is a life-threatening disorder that causes an abnormal layer of mucus to build up and coat bodily organs, especially the lungs and the pancreas. In the lungs, mucus restricts breathing and increases the risk of bacterial infections. In the pancreas, it blocks the release of digestive enzymes that help the body absorb food. Treatment has come a long way in recent years, but the median age of death is still only 40.

The disease is inherited when both parents are carriers of a defective gene — a phenomenon called autosomal recessive —  and the gene is the cystic fibrosis transmembrane conductance regulator (CFTR). A deletion of three nucleotides basically mutates the gene and elimates crucial amino acids on the cell protein. There are actually more than 1,700 different mutations that can lead to cystic fibrosis, but tests only pick up on the most common ones - so it's actually possible to be tested for a mutation, be told you're not a carrier, and end up passing the disease along to your child anyway. 

While the risk of heart disease can be somewhat mitigated by exercise and healthy eating, genetic factors can make heart disease impossible to avoid no matter how hard one might try.

For example, some inherited traits make it more likely that a person will accumulate fat deposits in their arteries, a problem which can lead to heart attack. Hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy (ARVC) are both inherited conditions from sarcomere protein gene mutations that affect the heart's rhythm, making it beat irregularly and potentially leading to heart attack and even death. As such, people who have a close relative who is diagnosed with any sort of heart disease are encouraged to get a screening to find out if they also have the disease. 

Because the birth defects caused by achondrogenesis are so severe, survival is just about impossible. There are three variations of the disease, each propagated by mutations in slightly different genes: TRIP11, SLC26A2, and COL2A1 (causing achondrogenesis type 1A, type 1B, and type 2, respectively). This condition, which is typically inherited from parents who are carrying a mutated gene, results in extremely short limbs and a very small torso. Most babies with this condition are stillborn or die shortly after birth due to respiratory failure. 

Huntington's Disease, also known as HD, is a deadly genetic condition that causes nerve cells to deteriorate. The symptoms have been described as having ALS, Parkinson’s and Alzheimer’s at the same time — basically a degeneration of the body's motor functions. It's a brutal disease that causes personality changes, mood swings, depression, unsteady gait and involuntary movements, forgetfulness and impaired judgment, slurred speech, difficulty in swallowing, and major weight loss. Death is usually caused by pneumonia or choking, both serious side effects of the condition. 

Having one parent with HD means a 50% chance of being a carrier for the faulty gene that causes the condition. Because of this, entire families can be gravely affected by HD. There is currently no cure, although there are therapies that can slow the disease's progression.

Perhaps the most terrifying thing about sickle cell disease is the array of complications it can cause. It's an inherited blood disorder caused by abnormally-shaped hemoglobin, the protein that carries oxygen throughout the body. It can affect nearly every single part of the body, with symptoms that include chronic pain, strokes, sexual problems, infections, heart attacks, gallstones, vision loss, anemia, organ damage, and more.

In the US, every infant is tested for sickle cell at birth, so that treatment can begin right away if necessary. The illness is most common in people of African descent, though it can occur in people from other racial groups, and it's estimated that between 70,000 and 100,000 Americans have this disease.