Introduction

Canavan disease is a type of genetic disorder where developmental delays appear in infancy.¹ Cognitive and motor functions, and typical physiological actions such as swallowing, become progressively more difficult and eventually regress until it is fatal, with the majority of mortalities occurring before adulthood.^1,2 The responsibility to take care of the affected child often falls on family members, particularly parents. This burden can negatively impact the psychosocial aspects of the family's life, creating a high level of negative emotions, which leads to a lower quality of life.^3-6 These effects, along with some additional resources, will be discussed in this article. 

What is Canavan disease?

Canavan disease is a genetic condition that affects the nervous system.¹ There is a mutation in a gene, called the ASPA gene, located on chromosome 17, which is responsible for a particular enzyme called aspartoacylase.¹ This causes an absence of the functional enzyme, leading to a buildup of the amino acid metabolite, N-acetylaspartic acid, in the brain.¹ This accumulation is associated with the breakdown of oligodendrocyte function.¹ These are essential cells in the central nervous system that create the insulating layer called myelin that wraps around nerve cells, to help the transmission of signals and information across the nervous system and throughout the body.⁷ 

Therefore, without functioning oligodendrocytes, myelin is not adequately produced, and neuronal signals are disrupted.⁷ The exact developmental process of Canavan disease is not fully known, and more scientific research is required to have a better understanding.¹

Canavan disease is part of a group of genetic disorders known as leukodystrophies due to its impact on the white matter in the brain.^1,8 The brain can be structurally divided into two components, the white and grey matter.⁹ The white matter consists of nerve fibres called axons, with myelin insulation, connecting to different parts of the brain, whilst the grey matter mainly consists of neuronal cell bodies and axons without myelin.^7,9

Since Canavan disease affects the myelin production by oligodendrocytes, the volume of white matter in the brain is reduced.¹ This hugely affects the motor and cognitive development and function, causing the patient to have difficulties in moving, controlling their own limbs, and learning.¹

Although it is a rare disease, Canavan disease progresses to become increasingly severe and is ultimately fatal.¹ It has a recessive inheritance, where both parents of the patient need to pass down the gene for this condition to occur.¹ It appears to have the most significant prevalence in the Ashkenazi Jewish community, with an estimated rate between 1 in 6000 to 1 in 14000, but has been observed in other populations as well.^1,10 

What are the signs of Canavan disease?

Canavan disease usually presents in babies before they turn 1 year of age, starting from 3 to 5 months of age.¹ In the first few years of life, some signs will be evident, such as:^1,11

• Poor control and support of the head
• Poor muscle tone, also known as hypotonia
• Macrocephaly, where the head circumference is abnormally large 
• Delays in development, such as their ability to stand, walk, use their hands intentionally, and communicate through language
• Difficulty in fixing and following objects when looking
• Blindness after 6 months of age
• Seizures of various types are experienced by the majority of patients
• Difficulties in feeding and swallowing 
• Increased irritability 
• Sleep disturbances, where there is difficulty in initiating and maintaining sleep

Typically, prognosis is poor, and life expectancy is reduced.¹ A quarter of patients do not live past 10 years of age, and most die within the first 20 years.^1,2 Even in patients who progress through childhood and into adolescence, development that was previously gained will be lost.¹ 

How is Canavan disease treated?

Unfortunately, at present, there is no cure for Canavan disease.¹ Treatment plans are typically based on managing symptoms and supportive care.¹ To prevent and treat seizures, anti-epileptic medications may be prescribed.¹ To allow nutrition and hydration to continue, a feeding tube is commonly used.¹ Physical therapy and botulinum toxin injections may be employed to help with muscle hardening and spasticity.¹

What are psychosocial impacts?

As a patient or a carer of someone who requires support for their condition, not only are their health, but also other aspects of their lives, such as social and psychological needs and relationships, are impacted.¹² It is important to recognise these factors that affect the quality of an individual’s life.³ This can play a significant toll on an individual’s mental health, which may then manifest into physical health issues as well.¹³ 

What are some emotional impacts on families of patients with Canavan disease?

Receiving news that your child or a family member has a progressive and fatal disease is never easy. Genetic disorders can be challenging to understand, especially when the process of disease progression still requires further research.¹ Parents of children with leukodystrophic disorders may have feelings of:^3-6

• Stress
• Unfairness or injustice of their situation
• Blame and guilt
• Loneliness and isolation
• Loss
• Shame and stigmatisation 
• Anger 
• Exhaustion 

The more frequent and severe these feelings are, the more it is associated with a lower quality of life in parents looking after children with leukodystrophies.³ 

Parents and caregivers may also feel unheard by others in the community and in a healthcare setting. It is suggested that healthcare experts may communicate more interest in the technical scientific aspects of this condition, whilst parents are more concerned with practical management and issues with quality of life for the child and themselves.⁶ This may come across as a lack of sensitivity to the burden of caring for a child with Canavan disease, even though the ultimate goal for everyone is to provide better healthcare treatments and support to those in need.⁶

Alongside the physical demands of supporting a child with a developmental disorder and disability, there may also be difficulties in balancing work and taking time to care for the child, especially if there are other children in the family as well. Furthermore, feelings of burnout and exhaustion can be exacerbated when the parent or caregiver does not get any time or space for their own personal lives.¹⁴

Future pregnancies

As Canavan disease is a recessive genetic disorder, both parents of the patient will carry the gene for this condition. This means there is a 1 in 4 chance of giving birth to another child with Canavan disease, and a 50% chance of the child being a carrier for this gene, where they will not have the disease but can potentially produce children with Canavan disease if their partner is also a carrier.¹⁵ This may affect the parents’ decision on family planning and the implications of tests that may need to be done if they choose to have more children.¹⁵ Genetic counselling and testing are useful to manage pregnancies and help plan for the support required for the child.¹⁵ Some tests offered by the NHS include preimplantation genetic testing and prenatal testing.¹⁵ 

Are there additional resources and online support available for family members and caregivers?

It is very easy to feel alone and unsupported as a parent or carer of a child with Canavan disease. Some charities offer more information and assistance. NHS offers mental health counselling through a self-referral system, which may help caregivers to discuss and process challenging feelings that could be difficult to verbalise. Below are some charities that provide additional information and support for those who may be impacted by this condition or for those who simply want to know more.

• The Canavan Foundation
• We are Alex, The Leukodystrophy Charity
• The Brain Charity
• Metabolic Support UK

Through these organisations, parents can find others who have similar experiences and support each other. They often hold events and support groups in the local community, which can be more suitable for families to attend.

Summary

There can be a substantial physical and mental toll on families and caregivers of patients with Canavan disease. This can put a strain on interpersonal relationships within the family and the community. Feelings of stress, injustice, and shame are common signs of the emotional impact experienced by the family of the child. It is important to feel at ease to verbalise challenges of caring for family members who have this condition and to feel heard by those around them and in a healthcare setting. There are charities and different services available in the NHS that can help to support caregivers. Please do not hesitate to reach out!