It looks like you are using an older version of Internet Explorer which is not supported. We advise that you update your browser to the latest version of Microsoft Edge, or consider using other browsers such as Chrome, Firefox or Safari.

Examples of Monogenic Diseases


Cystic Fibrosis (CF)

CF is a genetic disease caused by mutations in the CFTR gene. The CFTR gene provides instructions for the body to make protein for a channel involved in the control of water transport in tissues. This is necessary for normal, free-flowing mucus. When this gene is not working properly, cells that line the insides of the lungs, pancreas, and other organs make thick, sticky mucus. As a result, people with CF experience breathing problems and damage to airways, increased risk of lung infections, and digestive problems.


Duchenne Muscular Dystrophy (DMD)

DMD is a genetic condition and is one of nine types of muscular dystrophy. It is caused by mutations in the DMD gene and almost exclusively affects males. The DMD gene provides the body with instructions for making a protein called dystrophin, which is important to certain muscle cells. As a result, boys with DMD experience muscle weakness that appears in early childhood and quickly worsens. Boys with DMD may have delayed motor skills, often depend on a wheelchair by their teenage years, and may experience heart complications.


Friedreich's Ataxia (FA)

FA is a rare genetic disorder characterized by progressive damage to the nervous system. FA causes degeneration of the spinal cord and peripheral nerves. As a result, messages cannot be relayed between the brain and the body. This causes increasing problems with movement and balance, eventually leading to wheelchair confinement. While cognitive (thinking) functions remain unaffected, one-third of sufferers of FA have heart issues and some develop diabetes. FA is caused by a mutation in the gene FXN, which produces a protein called frataxin. Frataxin is found in the energy-producing mitochondria.


Genetic Amyotrophic Lateral Sclerosis (ALS)

ALS is a disease that affects the nerve cells that control muscle movement. In most people, the cause of ALS is unknown. However, in some cases, ALS is inherited and can be caused by a single, mutated gene with multiple candidate genes. There are many different genes that, when they have an error, have been shown to cause ALS. Regardless of the genetic cause, over time, muscles lose their strength, and the disease can become life-threatening.



Hemophilia is a genetic bleeding disease that mostly affects males. There are two major types, hemophilia A and hemophilia B. Hemophilia A is caused by changes in the F8 gene, while hemophilia B is caused by changes in the F9 gene. These genes are responsible for making important proteins that are needed for blood to clot properly after an injury. People with hemophilia may experience continuous bleeding after an injury or even spontaneously without an injury. Bleeding in the joints, muscles, brain, or internal organs can be especially dangerous.


Huntington’s Disease

Huntington’s disease is a genetic disease that causes the progressive breakdown (degeneration) of nerve cells in the brain. It is caused by mutations on the huntingtin (HTT) gene. The HTT gene provides instructions for making a protein called huntingtin, which plays an important role in nerve cells (neurons) in the brain. The symptoms of Huntington’s disease include uncontrolled movements, emotional problems, and loss of the ability to think and understand (cognition). 


Inherited Retinal Disorders/ Dystrophies (IRDs)

IRDs are a group of genetic diseases that cause progressive vision loss and can lead to blindness. The clinical appearance of the disease and how quickly it progresses depends on the type of IRD. The most common type, retinitis pigmentosa, can be caused by over 100 genes with varying functions. 


Rett Syndrome (RTT)

RTT is a genetic disease that occurs mainly in girls and affects how the brain works and develops. It is caused by a mutation in a single gene called the MECP2 gene. Girls with RTT may sometimes appear to develop normally from the time they’re born up to between 6 and 18 months of age. After that, they quickly lose mental and physical abilities, and can develop severe problems with language, communication, and coordination.


Sickle Cell Disease

Sickle cell disease is one of the most common monogenic diseases. This blood disorder is caused by an alteration in the HBB gene. The alteration changes the shape of red blood cells and leads to their early death. The disease presents in early childhood and must be carefully managed throughout life.


Spinal Muscular Atrophy (SMA)

SMA is a genetic condition that affects nerves and muscles. It is caused by a missing or nonworking SMN1 gene. The SMN1 gene is responsible for producing a protein. When the protein levels are reduced, motor neuron cells stop working and die. Over time, muscles can become so weak that movement, eating, and breathing become difficult. This serious muscle weakness, especially in the muscles used to breathe, can be life-threatening.