The Most Common Genetic Diseases

Certain forms of arthritis, such as osteoarthritis, have a strong genetic component. Osteoarthritis develops when the genes responsible for collagen production mutate. As a complex genetic disorder, arthritis involves the mutation of multiple genes at once.

Additional factors can influence the onset of arthritis as well, including joint injuries, obesity, and aging. Symptoms that are commonly associated with arthritis include a reduced range of motion, joint stiffness, swelling, loss of flexibility, and pain in the affected joints.

Genetics play a significant role in autism spectrum disorder (ASD). Because this condition is also heavily influenced by a person's biological makeup and environment, it is considered a complex genetic disorder. Those who have ASD are usually diagnosed at a very young age, when they first begin exhibiting symptoms.

ASD is an umbrella term, and the long list of symptoms varies greatly in type and severity. Generally speaking, though, some of the most common signs of ASD include repetitive behaviors, problems with effective communication, and impaired social skills.

Cystic fibrosis targets the cells that produce mucus, causing mucus to accumulate inside various organs, such as the pancreas and lungs. Many people with cystic fibrosis have difficulty breathing due to a buildup of mucus in their airways. Other symptoms include an inability to gain weight, a persistent cough, frequent sinus infections, wheezing, and loose stools.

Cystic fibrosis is classified as a single-gene mutation. It develops as a result of a singular defective gene, which can be passed down through many generations.

Sickle cell disease is an inherited disorder that causes deformed red blood cells. Eventually, the cells break down and die, leading to an ongoing red blood cell shortage. This prevents hemoglobin from transporting enough oxygen to tissues, which can lead to fatigue, frequent infections, and other symptoms.

Another hallmark of sickle cell disease is a condition known as sickle cell crisis: episodes of extreme pain that vary in duration and intensity.

A well-known chromosomal disorder, Down syndrome occurs when someone is born with an extra twenty-first chromosome. This condition is accompanied by lifelong intellectual and developmental delays. Research points to Down syndrome as the most common cause of childhood learning disabilities.

This genetic disorder is commonly characterized by distinct facial features, a short height, excessive flexibility, a small head, and poor muscle tone. However, symptoms vary from one individual to the next, and each person's experience with this condition is unique.

Diabetes is a common condition with a strong genetic component. However, in the case of Type 2 diabetes, lifestyle also affects the likelihood of developing the condition. Diet and exercise habits, especially, play a role. This makes diabetes a complex genetic disease.

Because a person's environment partly influences whether they'll develop Type 2 diabetes, acquiring healthy habits early on can help prevent this type of the disease. This includes eating a balanced diet and maintaining a healthy exercise routine.

Migraines are debilitating headaches that can be severe enough to leave a person bedridden. These headaches tend to worsen with exercise, noise, lights, and even certain smells. Common symptoms of migraines include throbbing pain, fatigue, nausea, irritability, numbness, and visual abnormalities, such as seeing flashing lights or auras.

Studies have shown that if at least one parent suffers from migraines, their child is 50–75% more likely to suffer from them as well.

Coronary artery disease (CAD) disrupts the functioning of your coronary arteries. Your heart depends on these vessels to supply enough blood for it to work properly. As CAD progresses, patients experience a buildup of plaque inside their coronary arteries, causing them to narrow or become blocked.

If any of your relatives have heart disease, this could increase your risk of developing CAD. It's also important to keep an eye on diet and exercise habits, as these also factor into the likelihood of having heart disease.

Late-onset Alzheimer's disease is another example of a complex genetic disease. The most common cause of dementia, Alzheimer's results in a gradual decline in cognitive ability, memory, learning, and organization skills. In time, it can negatively impact a person's ability to complete basic everyday tasks.

The link between genetics and Alzheimer's is strongest in cases of late-onset Alzheimer's, where symptoms begin to appear when a person is 65 or older.

Certain types of cancer are considered inherited diseases, such as prostate, breast, and colon cancer. These diseases arise when there is a genetic mutation found in the sperm or egg cell while it is being fertilized.

Fortunately, there are ways to spot inherited cancers before they spread. Genetic testing, screening, and risk assessment are all highly effective methods. Knowing your family's medical history can help you determine which symptoms you should be watching for and which screening tests can help catch any issues early.