Gene therapies can replace the single nonworking gene, so that it can now provide its necessary function

If you’ve spent any time reading up on or living life with a rare condition, chances are you’ve come across the terms “genetic disorder,” and “gene therapy.” But what exactly do they mean? And what differentiates them from other diseases and treatments?

A genetic disease is caused by nonworking or missing genes. Scientists recently found that genes may play a part in many diseases. Genetic diseases can be the result of a mutation in one gene or multiple genes. Some mutations that are inherited from one or both parents. Other diseases are caused by mutations that occur randomly, or due to an environmental exposure (such as cigarette smoke—which causes cancer).

Genetic diseases that are the result of a single, nonworking or missing gene make an easier target for gene therapies. These therapies can replace the single nonworking gene, so that it can now provide its necessary function.

Some of the one-gene group of rare genetic disorders being studied for gene therapies are:

• Cystic fibrosis — caused by a mutation in the CFTR gene, which makes the body unable to produce a specific protein essential for free-flowing mucous. A thick sticky mucous builds up in the lining of the lungs.

• Duchennes Muscular Dystrophy — the result of a mutation of the DMD gene, necessary for producing a protein responsible of muscle development.

• Gauchers Disease — caused by one gene, GBA1, but can have many different mutations, and therefore there are many different types of the disease. There are two categories of Gaucher disease: those that affect the nervous system (Types 2 & 3) and those that do not (Type 1).

• Hemophilia — there is a type A and type B, which are both caused by a mutation in either the F8 or the F9 genes. Because of this absent gene, a person with hemophilia is missing an important element needed for their blood to clot after an injury.

• Sanfilippo Syndrome (MPS IIIa) — caused by a non-functional or missing SGSH gene which produces an enzyme that’s essential for processing sugar molecules. This causes a buildup in many areas of the body, especially the brain, leading to neurological and developmental issues.

• Spinal Muscle Atrophy (SMA) — caused by a missing or non-functional SMN1 gene responsible for a protein needed by the nerves that are connected to muscle function (motor neurons). Over time, these motor neurons die, and the muscles required for walking, talking, eating, and breathing eventually don’t work.

Clinical studies for gene therapies are in development for many orphan diseases. Some of these studies are specifically looking for young children, and are being conducted in centers that specialize in the study of genetic diseases in children.

There are gene therapy studies for rare blood diseases like Sickle Cell Disease, Hemophilia, and Wiskott-Aldrich Syndrome, and for neurological disorders like Sanfilippo Syndrome, and muscular disorders like SMA. Although gene therapies do not cure the disease, they do address the root cause of the disorder. They are also given as a one-time treatment, which can “fix” the problem caused by the missing gene. However, since most of gene therapies are relatively new, how long the effect, or the “fix,” will last is still among the unknowns. Centers and researchers who are involved in clinical studies of gene therapies are highly knowledgeable about genetic diseases and gene therapies, and are likely to have the most experience in using them.

If you are interested in seeing if there are any studies available related to your condition, you can search clinicaltrials.gov for the name of the condition and, under any other search terms: gene therapy. In the future, KnowRare will provide additional guidance on how to find out more about gene therapies.

Written By
Know Rare Team

Sources:

NIH National Human Genome Research Institute
https://www.genome.gov/Clinical-Research/Current-NHGRI-Clinical-Studies