What is Late Onset Tay-Sachs
Late Onset Tay-Sachs (LOTS), also known as Adult Onset Tay-Sachs, is a very rare form of Tay-Sachs which usually occurs in individuals in their 20s and early 30s. Like all forms of the disease it is due to a reduced level of the Hexosaminidase A (Hex-A) enzyme. You can read what Tay-Sachs is here.
LOTS is frequently misdiagnosed, and is usually non-fatal. It is characterized by unsteadiness of gait and progressive neurological deterioration. The symptoms of LOTS, which present in early adulthood include speech and swallowing difficulties, unsteadiness of gait, spasticity, cognitive decline, and psychiatric illness.
As it is very difficult to identify, when an individual is finally given the diagnosis they often look back to their childhood and notice symptoms which were not obvious at the time. A common early sign is not being athletic and/or speech difficulties or a stutter as a child or teenager.
One early indicator which can lead to a LOTS diagnosis is a mental health problem – although this will just be the beginning of a long road to the final diagnosis. About 40% of affected adults experience mental health symptoms such as bi-polar or psychotic episodes.
Like all forms of Tay-Sachs there is a loss of skills – although in LOTS this takes much longer than a child with the Classic Infantile form. Over a prolonged period of time adults with LOTS slowly decline and require more mobility assistance. Although many experience speech and swallowing difficulties only a few will eventually require a feeding tube.
How is is diagnosed
As LOTS is very hard to diagnose, individuals can go many years before finding out they suffer from it. It is very common for LOTS to be misdiagnosed as Multiple Sclerosis, ALS or Friedreich ataxia.
Adults affected by the LOTS form of Tay-Sachs do not exhibit the tell-tale cherry-red spot. This can make the road to diagnosis long and challenging. Unfortunately many healthcare providers are not aware of the rare adult forms of these diseases and dismiss the initial diagnosis due to the age of the patient.
However, like all forms of Tay-Sachs, the LOTS form is only confirmed by a blood test to see the actual levels of Hexosaminidase A (Hex-A) they have.
If the blood test confirms LOTS then all members of the individuals 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 the affected individual to be a carrier.