What are the different types of Tay-Sachs
Tay-Sachs is a genetic disorder caused by the absence of a vital enzyme known as Hex-A. This missing enzyme causes cells to become damaged, resulting in progressive neurological disorders.
The form or type is determined by the age of the individual when symptoms first appear. Only one form of Tay-Sachs occurs in a family. If a child has Infantile, older siblings are not at risk to develop Juvenile or Late Onset Tay-Sachs later in life.
- Classic Infantile – symptoms appear around 6 months of age
- Juvenile – symptoms typically appear between ages 2 and 5, but can occur anytime during childhood
- Late Onset – symptoms typically appear in adolescence or early adulthood, but can appear later
A baby with classic Infantile Tay-Sachs appears normal at birth and typically continues to develop like any other child for the first six months. However, after this development slow and parents may notice a reduction in vision and the baby continues to have a prominent startle response.
Children with Infantile Tay-Sachs gradually regress losing skills one by one. Over time they are unable to crawl, turn over, sit or reach out. Other symptoms include loss of coordination, progressive inability to swallow and difficulty breathing.
Most children experience recurrent seizures by age 2 and eventually lose muscle function, mental function and sight, becoming mostly non-responsive to their environment.
Early symptoms of Juvenile Tay-Sachs include lack of coordination or clumsiness and muscle weakness such as struggling with stairs. A child may also exhibit slurred speech, swallowing difficulties and muscle cramps.
Children with Juvenile Tay-Sachs slowly decline, losing their ability to walk, eat on their own and communicate. Children are prone to respiratory infections and often experience recurrent bouts of pneumonia while many have seizures.
Juvenile Tay-Sachs has a broad range of severity. In most cases, the earlier the first signs are observed, the more quickly the disease will progress. For example, a child with first symptoms at age 2 will decline faster than a child with first symptoms at age 5.
Early symptoms of Late Onset Tay-Sachs (LOTS) include clumsiness and muscle weakness in the legs. Once diagnosed, adults often reflect back to their childhood and may notice experiencing symptoms much earlier such as not being athletic and/or speech difficulties or a stutter as a child or teenager.
The mental health symptoms may present first which can lead to an especially long road to diagnosis. About 40% of affected adults experience mental health symptoms such as bi-polar or psychotic episodes.
Over time adults with Late Onset Tay-Sachs slowly decline. Adults frequently require more mobility assistance, i.e. cane to walker to wheelchair. Many experience speech and swallowing difficulties but few require a feeding tube.
At THE CATS FOUNDATION we want to provide as much information as possible. However, as a new charity and with a limited number of people able to add content to the website we do require some time to do this. We plan to add an individual post for each form of Tay-Sachs to the frequently asked question section on the website so please be patient with us and we will do it as quickly as we can.
The information on the types of Tay-Sachs has kindly been provided by the NTSAD.