7 of The Most Common Genetic Diseases

Scientists attribute the cause of all genetic disease to a permanent alteration in a gene’s DNA sequence that renders it different from that found in most people. Genetic mutations can range in size from a single base pair of DNA, to a large section involving multiple genes.

The effects of genetic mutations varies greatly, with some people exhibiting few or no symptoms and others being seriously affected. Here we look at some of the most common genetic conditions.

1. Muscular Dystrophy

Muscular dystrophy is a muscular disease that weakens and eventually breaks down skeletal muscle. There are some thirty types of the disease which can affect different parts of the body.

The most common type is Duchenne Muscular Dystrophy, which affects males who typically present symptoms around the age of 4 years. The disease affects around 1/5,000 males at birth.

There is no cure for this genetic disorder, though braces, physical therapy, medication and corrective surgery can often help alleviate symptoms.

2. Severe Combined Immunodeficiency Disorder (SCID)

Also known as alymphocytosis, experts attribute this genetic disorder to numerous genetic mutations that affect the development and function of the body’s B and T cells. These cells are critical to the body’s immune system and capacity to fight disease.

Sometimes referred to as “bubble baby disease,” people with this disorder are very vulnerable to infectious disease. Because many people with SCID have virtually no immune systems, they often have to live in sterile environments.

3. Ectrodactyly

Ectrodactyly, or cleft hand as it is commonly known, involves absent or deficient middle digits of the hands or feet resulting in a characteristic claw-like appearance. The severity of symptoms can vary greatly, from mild restriction of movement in some, to the presence of only a finger and thumb and a complete lack of mobility in others. Surgical treatments are available to improve function and appearance.

4. Jackson-Weiss Syndrome

Jackson-Weiss syndrome typically causes foot abnormalities and premature fusion of bones in the skull. Geneticists have traced the origin of this genetic disease to a mutation in the FGFR2 gene. This gene is responsible for producing fibroblast growth factor receptor 2, an important protein that provides crucial signals in the developing embryo.

The gene alteration associated with Jackson-Weiss syndrome causes prolonged signaling by altering the protein, resulting in the premature fusion of bones. Secondary complications include hydrocephalus and cognitive impairment. There is no cure, though experts often recommend surgery to treat the symptoms.

5. Huntington’s Disease

Huntington’s disease is a genetic disorder that interferes with the function of various parts of the brain. Scientists attribute the disorder to a genetic mutation that causes damage to parts of the brain over time. Huntington’s disease is a degenerative genetic condition. The life expectancy of a person who has Huntington’s disease is usually 20 years from diagnosis.

Symptoms usually begin in later life, between the ages of 30 and 50, though in some instances can start earlier or later. Symptoms include involuntary jerks, depression, difficulty in concentration, memory lapses, clumsiness and stumbling.

There is no cure for Huntington’s disease, though medical practitioners may prescribe medicine and recommend physiotherapy to treat symptoms,

6. Sickle Cell Anemia

Sickle cell anemia is a group of diseases that affect hemoglobin. Hemoglobin is crucial in the delivery of oxygen throughout the human body. People with sickle cell anemia have distorted hemoglobin molecules, which appear in the characteristic crescent shape. These anatomical changes result in the premature breakdown of red blood cells. This in turn leads to anemia.

Symptoms of anemia include fatigue, shortness of breath and delayed development and growth in infants. Misshaped hemoglobin molecules can get stuck in capillaries, causing deprivation of oxygen to vital organs and damaging them.

A potentially fatal secondary complication of sickle cell anemia is pulmonary hypertension, or high blood pressure within the blood vessels supplying the lungs, which can lead to heart failure. This complication affects around a third of people with sickle cell anemia.

7. Cystic Fibrosis

Cystic fibrosis is the world’s most common genetic disorder. It typically affects the lungs but can also involve the liver, kidneys, pancreas and intestine. Other symptoms include clubbed fingers and infertility in males.

Cystic fibrosis results in an overproduction of mucus that accumulates in the lungs, causing shortness of breath, coughing and chest infections. The condition can sometimes cause bowel obstructions, malnutrition and stunted growth. Common secondary conditions include pulmonary hypertension and heart failure.

Cystic fibrosis is a condition that affects both men and women. An estimated 97 percent of males with cystic fibrosis are infertile, though not sterile. This means that they are able to have children via IVF treatment. Around 20 percent of females with cystic fibrosis have fertility problems.

With approximately 30,000 individuals diagnosed with the disorder in the US and an estimated 1/25 people carrying the associated gene mutation, a great deal of research has been conducted into cystic fibrosis with the aim of finding a cure. Breakthroughs in gene therapy give scientists hope that they may one day be able to introduce normal gene copies to effectively reprogram affected cells, overwriting the mutation and making cells function properly.