Classic Infantile Tay-Sachs is the earliest presenting form of Tay-Sachs in children and is the result of a lack or severely reduced level of the Hexosaminidase A (Hex-A) enzyme. You can read what Tay-Sachs is here.
The signs of Classic Infantile Tay-Sachs in a child usually appear after they are 6 months old. Up until this point the child appears to be developing normally but this development then begins to slow. Other physical signs of Tay-Sachs at this age include a prominent startle reflex to loud noises and also a gradual reduction in vision.
A child with Classic Infantile Tay-Sachs gradually regress and they begin losing skills one by one – such as the ability to roll over, sit or reach out. Other symptoms include loss of coordination, progressive inability to swallow and difficulty breathing.
As the disease progresses most children experience recurrent seizures by age 2 and eventually lose muscle function, mental function and sight. Sadly, they become non-responsive to their environment.
How it is diagnosed
Like all forms of Tay-Sachs, the Classic Infantile form is only confirmed by a blood test to see the actual levels of Hexosaminidase A (Hex-A) they have. All other signs may point to Tay-Sachs before this test is done, however it may be that the child has another metabolic condition which is why the blood test is important in the diagnostic process.
If the blood test confirms Classic Infantile Tay-Sachs then all members of the parents family should be tested to determine whether they are also a carrier of the disease. As an autosomal recessive disease it requires both parents of a child to be a carrier.