If you and your partner are looking to start a family or add to your existing one, the Canavan Foundation strongly recommends preconception carrier screening that will provide you with critical information to help build a healthy family.
Autosomal recessive diseases are genetic disorders that are passed down from both parents to their children, but which only manifest when a person inherits two copies of the defective gene — one from each parent. These diseases are serious, often leading to severe health challenges or even early death. It is essential to understand the severity of autosomal recessive diseases and the risks they pose, particularly for individuals starting or adding to their families.
In this article, we will explore what autosomal recessive diseases are and why they are so dangerous, explain the importance of genetic screening for couples looking to get pregnant, and focus on one particularly devastating disease: Canavan disease.
In autosomal recessive diseases, the defective gene resides on one of the 22 non-sex chromosomes, known as autosomes. These diseases require that both copies of a gene — one inherited from each parent — be faulty for the individual to be affected. If a person inherits only one faulty gene, they are considered a carrier and typically show no symptoms. However, if both parents are carriers, there is a 25% chance with each pregnancy that their child will inherit two faulty copies and develop the disease. Because of this, it is crucial for couples to get screened if they are planning to start a family.
Autosomal recessive diseases are dangerous because they can remain hidden in families for generations. Carriers usually do not exhibit symptoms, so the disease may not be detected until it manifests in a child. Because these diseases can cause serious or life-threatening conditions, early diagnosis and genetic counseling are crucial for families.
Many autosomal recessive diseases are progressive, meaning they worsen over time, often leading to irreversible damage to organs and systems. Some of the diseases can result in early death. This fact underscores the importance of awareness and preconception genetic carrier screening.
While autosomal recessive diseases are relatively rare, they encompass a wide variety of conditions. Some of the most well-known examples include:
Each of these diseases presents significant health challenges, affecting quality of life and requiring ongoing treatment. However, Canavan disease stands out as one of the most dangerous autosomal recessive diseases due to its harmful effects on those who have it.
One of the most severe autosomal recessive diseases is Canavan disease. This rare genetic disorder primarily affects the brain, leading to profound developmental delays and physical disabilities. Canavan disease is caused by mutations in the ASPA gene, which impairs the production of aspartoacylase, an enzyme essential for brain development.
Children with Canavan disease are often born seemingly healthy but begin to exhibit signs of neurological deterioration within the first few months of life. These signs can include:
Unfortunately, there is currently no approved treatment or cure for Canavan disease, and some children affected by this disease die before age ten, although others can survive into their teens or twenties.
The rarity and severity of Canavan disease make it particularly challenging for families. Genetic carrier screening and counseling are essential for identifying carriers, ideally before conception. Previously, carrier screening was particularly recommended in families with Ashkenazi Jewish ancestry, but current recommendations are that all individuals having children be screened before pregnancy.
Genetic counseling plays a critical role in identifying carriers of autosomal recessive diseases. All couples can benefit from receiving carrier screening and counseling before having children. Screening can determine whether both parents are carriers of the same genetic mutation, a situation that significantly increases the risk of having a child with an autosomal recessive disease. If two parents turn out to be carriers of the same genetic mutation, with each pregnancy they will have a 25% chance of having a child with the disease.
By understanding their genetic risks, couples can make informed decisions about family planning. In some cases, early detection and intervention may help reduce the severity of symptoms or provide early access to treatments that improve quality of life. Additionally, educating the public about the importance of preconception carrier screening and genetic counseling can lead to prevention of these very serious diseases .
As research progresses, there is hope that new treatments and therapies will be developed to help those affected by autosomal recessive diseases.
Support organizations, such as the Canavan Foundation, provide vital resources for families dealing with Canavan disease and other autosomal recessive diseases. These organizations offer emotional support, financial assistance, and information about ongoing research into potential treatments and cures.
By understanding the nature of autosomal recessive diseases, recognizing the importance of genetic carrier screening and counseling, and supporting organizations like the Canavan Foundation, we can help prevent these devastating conditions, improve the lives of those living with the disease, and work toward finding treatments and cures.
The Canavan Foundation is dedicated to educating at-risk populations about Canavan disease and other genetic diseases and the reproductive options available to carrier couples. We encourage preconception genetic carrier screening whenever appropriate. In addition, the foundation supports research towards treatments and a cure for Canavan disease. You can look into getting screened today or support our critical work by making a donation!