Wiedemann-Steiner syndrome (WSS) includes distinctive facial features, growth delay, and intellectual disability. Signs and symptoms vary, but facial features may include thick eyebrows, wide-spaced eyes, and narrow eye openings.
Will gene therapies be able to identify and potentially help WSS? Here are several novel approaches that may allow for cutting-edge changes in science. The future is bright!
What is a genetic disease?
Some genetic diseases are caused by a malfunctioning or missing gene or genes. Genes are made up of deoxyribonucleic acid (DNA) and come in pairs, one from each parent. Genes store the code—the information and instructions—the body needs to make proteins. Nearly every function of the body is made possible by proteins. When a piece of DNA is missing or changed, it can alter protein production. The protein may no longer be able to carry out its normal function. So even if a single protein is missing, in short supply, or made wrong, the effect on the body can be harmful.
A genetic disease can be passed down from one or both parents or can be a result of random errors in the body’s genes.
How can gene therapy help?
Gene therapy is an evolving strategy for disorders caused by a missing or faulty gene and may involve addition, inhibition, editing, or functional replacement of a gene.
Gene therapies can be one-time treatments and are designed to target the genetic root cause of diseases.
Gene Editing & Therapies may hold some answers?
The Goal of Gene Editing and Options
What is the goal of gene inhibition?
Gene inhibition therapy aims to stop a gene that is toxic to the cells.
For example, an oncogene is a type of gene that can sometimes cause cancer by stimulating uncontrolled cell growth. Interfering with that oncogene’s ability to function could prevent such uncontrolled cell growth and stop the spread of cancer.
What is the goal of gene editing?
The goal of gene editing is to prevent and treat disease by making small, precise cuts to remove a sequence of deoxyribonucleic acid (DNA) to turn off a gene that is making a harmful protein, turn on a gene to make more of a needed protein, or fix a mutated gene.
Gene editing is primarily used in the lab to better understand disease in humans. Scientists study how removing individual genes affects animals that share a significant amount of genetic code with humans (like mice). Because there are still many ongoing questions about the safety of gene editing and room for error with the technology, it has only been used in rare cases where no other options are available. For example, it is being investigated in sickle cell disease.
What is the goal of gene addition?
By aiding the body’s ability to fight complex diseases, gene addition aims to improve outcomes for people with complex disorders and infectious diseases, either on its own or in combination with other non-genetic treatments. For example, gene therapy for cancer may be used in combination with chemotherapy.
As more research is done, progress using gene addition for specific diseases may lead to new treatments for other similar diseases.
Possible applications
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
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.
Gene Therapy Studies & Trials
Pre-Qualify for pheEDIT study
Gene editing is a potential therapy for genetic diseases, which occur when a person’s own gene has a mutation that affects the normal biological function of the enzyme made from this gene. Specifically, gene editing is a technique in which a working copy of a gene is integrated into a person’s DNA in an effort to override the effect of the disease-causing gene, with the goal of preventing or potentially curing certain genetic diseases.
The pheEDlT study is evaluating the safety and efficacy of an investigational gene editing therapy known as HMl-103 in adults with PKU due to phenylalanine hydroxylase (PAH) deficiency. HMl-103 is designed as a one-time administration to integrate a functional PAH gene into the genome using the natural DNA repair process of homologous recombination (HR) and to express the PAH enzyme in liver cells.
Qualifications for Gene Therapy Trial:
- Have uncontrolled classical PKU disease due to PAH deficiency
- Are an adult aged 18 to 55 years old
- Are willing and able to maintain a stable Phe-restricted diet
- Are willing to commit to required study visits and tests for the duration of the trial
- Do not have contraindications to immunosuppressive therapy
CRISPR/Cas9-Mediated Genetic Engineering In Vivo
The ability to directly and precisely modify the genome of mouse and rat embryos using CRISPR/Cas9 technology has revolutionized rodent model generation. The first CRISPR-modified mice were created in 2013. While this technology has simplified the process of creating genetically engineered mouse and rat models, there are still many important details to consider to maximize the successful creation of a model that meets project goals. Taconic Biosciences has generated CRISPR-modified mice and rats for years and has produced hundreds of different models. Our experience and expertise ensure that your project will meet your needs.
CRISPR/Cas9 technology is rapidly evolving. Taconic uses the latest CRISPR/Cas9 genome modification methodologies to generate genetically engineered mice and rat models. For example, Taconic was the first commercial provider to license technology from the University of Nebraska. Taconic also holds CRISPR licenses from both ERS Genomics and the Broad Institute.
Three key advantages of CRISPR/Cas9 technology:
- Reduced timelines compared to ES cell-based gene targeting methods
- Reduced cost compared to traditional methods
- Ability to modify a broad range of genetic backgrounds including existing genetically engineered models and models on complex genetic backgrounds
