Symptoms of Tay-Sachs disease

In the most common form of Tay-Sachs disease,classic infantile Tay-Sachs disease, a babywill develop normally until they're around three to six months old.

One of the first noticeablesigns ofthe conditionis the appearance of ared dot at the back of their eyes. You may also notice that their vision seems poor, or that they're excessively startled by noises and movement.

It's likely that your baby will be much slower in reaching developmental milestones, such as learning to crawl.

Additional symptoms usually develop after about eight months of age and quickly become more severe. They include:

• increasing muscle weakness that progresses to Paralysis
• increasing loss of vision
• loss of hearing
• difficulties swallowing (dysphagia )
• muscle stiffness (spasticity)
• lack of interest in the world around them
• repeated fits (seizures)

Children with Tay-Sachs disease become increasingly vulnerable to infection, particularly lung infections. Many children die from a complication of an infection such as pneumonia .

Most childrenwith infantile onset Tay-Sachs disease diebefore they're four years old, because ofcomplications from repeated infections.

Rarer forms of Tay-Sachs disease

There are two much rarer forms of Tay-Sachs disease.

Juvenile form

In the juvenile form, the symptoms don't usually begin until a child is aged 2 to 10 years old.

Initially, problems develop with speech and motor skills, such as balance, walking and holding objects. Some children may also develop problems with vision.

As the condition progresses, the child will have repeated fits and experience dementia .

Most children with the juvenile form of Tay-Sachs disease eventually enter a vegetative state , where they're awake, but showing no signs of awareness. This usually happens between the ages of 10 and 15. The most common cause of death is a complication of an infection.

Late-onset form

The symptoms of late-onset Tay-Sachs disease develop later in life, usually during the teenage years or early adulthood.

Symptoms include:

• slurred speech
• loss of balance andco-ordination
• uncontrollable shaking of the hands ( tremor )
• muscle cramps and twitching
• muscle weakness

Aroundone in threepeople with late-onset Tay-Sachs disease also develop mental healthconditions, such as bipolar disorder or psychosis.They may see or hear things that aren't there ( hallucinations ) or believe things that aren't true (delusions).

Unlike other forms of the condition, late-onset Tay-Sachs disease doesn't alwaysshorten life expectancy.