Canavan Disease: Understanding the Rare Genetic Disorder

There are thousands of rare diseases affecting people all over the world that most of us have never even heard of. Despite their obscurity, these conditions can be just as devastating – and in some cases, even more so – than their more common counterparts. Unlocking their mysteries has recently been at the forefront of disease research labs. Today we zoom in on a rare disease that has a storied past, Canavan disease.

Canavan Disease Unveiled: What Is It?

First, we must go back to the year 1931, where we meet Myrtelle Canavan, an American pathologist, and medical researcher. She was a pioneer in neuropathology and authored a now-famous research paper that served as the first description of Canavan disease. The child she described had failed to gain weight, develop normally, and had a large head. He died after developing a high fever at 16 months of age. The autopsy of the brain revealed severe loss (degeneration) of the white matter and a “spongy” appearance under the microscope. Canavan was the first to describe the disease, which was later given her name to acknowledge her fundamental role.

Since its initial identification by Myrtelle Canavan, research into Canavan disease has grown tremendously. Over the years, scientists have made remarkable strides in unraveling the underlying causes and mechanisms of this disorder, and their efforts have paid off in new discoveries. They have discovered that Canavan disease causes brain atrophy, which refers to a progressive loss of nerve cells and connections in the brain, leading to significant cognitive and motor impairment. Typically starting in infancy, Canavan disease leads to a range of developmental delays, including weak muscle tone, poor head control, and an inability to roll over or sit up without assistance.

The significant progress made in Canavan disease research has not only improved our understanding of the disorder but has also opened up new avenues for potential treatment options. The knowledge gained about the underlying mechanisms of the disease has allowed the scientific community to hypothesize different treatment approaches to combat Canavan disease. While there is currently no cure for the disorder, research has shown promising results in developing treatments that can help alleviate symptoms and improve the quality of life for those affected. Gene therapy companies like Myrtelle are paving the way in Canavan research and conducting cutting-edge clinical trials. As studies in Canavan disease continue to progress, future discoveries may lead to even more effective treatments that may one day offer a cure for this rare and devastating disorder.

The Cause

What causes Canavan disease? To understand this properly, it’s helpful to break down the Canavan disease formation process:

1. The foundation lies in a mutation within the ASPA gene, which encodes the aspartoacylase enzyme through specific instructions.
2. Aspartoacylase plays an essential role in breaking down an important molecule called N-acetyl-L-aspartic acid (NAA) in the brain and thereby leading to the production of acetate and aspartate, building blocks that carry out important functions in the brain, including the production of energy (ATP).
3. Mutation in the ASPA gene results in a deficiency or absence of aspartoacylase, leading to the depletion of acetate and aspartate and a buildup of NAA in the brain.
4. These results of mutation in the ASPA gene lead to the destruction of myelin, an important fatty substance that forms a protective coating around nerve fibers in the brain, leading to a progressive loss of nerve function.
5. This process primarily affects the white matter of the brain, leading to a range of symptoms such as developmental delays, weak muscle tone, and a loss of motor function.

It’s important to note that the severity of Canavan disease symptoms can vary widely, depending on the degree of myelin destruction. Canavan disease follows an autosomal recessive inheritance, requiring two mutated ASPA gene copies (one from each parent) for the disorder to manifest. Now that we understand what the disease is, it’s important to know what to look out for when trying to spot it.

Canavan Symptoms to Look for

Below are the ten most common symptoms of Canavan disease.

1. Developmental delays: Infants with Canavan disease may experience delays in reaching developmental milestones, such as lifting their head, rolling over, sitting up, and crawling.
2. Weak muscle tone: Canavan disease can cause hypotonia, or weak muscle tone, making it difficult for affected infants to move or control their movements.
3. Abnormal movements: Affected infants may exhibit abnormal movements, such as jerking, twitching, or tightening from spasticity
4. Feeding difficulties: Infants may have difficulty feeding due to weak muscle tone and trouble swallowing.
5. Cognitive impairment: Canavan disease can cause significant cognitive impairment, leading to intellectual disability and developmental delays.
6. Vision and hearing problems: Some individuals may experience vision and hearing problems.
7. Seizures: Seizures are a common symptom of Canavan disease and can be difficult to manage.
8. Lack of head control: Infants may have difficulty controlling their head movements as motor skills are affected.
9. Sleep disturbances: Canavan disease can cause sleep disturbances, making it difficult for affected individuals to get restful sleep.
10. Progressive deterioration: It’s a progressive disorder, meaning that symptoms worsen over time, leading to significant impairment and disability.

Canavan Diseases Lasting Impact

The lasting impact of Canavan disease on families is one that cannot be fully expressed in words. The heartbreak, pain, and challenges that families face when caring for a loved one with this debilitating disorder are immense. However, despite the difficulties, families affected by Canavan disease demonstrate incredible resilience and unwavering commitment to their loved ones. With steady advances in research, there have been new methods of support and care family members can employ. Here are some examples that can potentially improve a person’s life:

1. Physical therapy: Physical therapy can help individuals with Canavan disease improve their strength, flexibility, and coordination, making it easier to move and control their movements.
2. Speech therapy: Speech therapy can help individuals with Canavan disease improve their ability to communicate, manage feeding difficulties, and reduce the risk of aspiration.
3. Occupational therapy: Occupational therapy can help individuals with Canavan disease maintain or improve fine motor movement such as grasping.
4. Support groups: Support groups can provide a safe and supportive space for individuals and families affected by Canavan disease to connect, share experiences, and receive emotional support.

While Canavan disease may continue to pose challenges for families, ongoing research and continued support systems are vital. There is hope in the scientific-medical community that one day, a cure for Canavan disease will be found, and families affected by this disorder will be able to live their lives without the burden of this devastating condition. Until then, let us continue to support Canavan disease research and look toward a hopeful future.