Tay-Sachs Drew Sivertsen

History Tay-Sachs is named after two physicians Warren Tay – was an ophthalmologist who was the first to discover a red dot on the retina of one of his patients in This red “cherry spot” is a telltale sign of TSD Bernard Sachs- was a neurologist who studied and was able to determine the changes that took place inside the cells of Tay-Sachs Disease. He also recognized that was an inherited condition that ran in families ( European (Ashkenazi) Jewish )

Diagnosis Before birth – Tay Sachs can be diagnosed by Amniocentesis - sample of fluid which surrounds the fetus ( between 16 and 18 weeks of pregnancy ) Chorionic villus sampling – a sample of cells of the fetus from the placenta ( about 10 weeks into pregnancy ) All Tay-Sachs patients will have a red dot or “macula” (oval shaped) on the back of their retina Without molecular experiments, the red dot is the only definitive diagnosis of TSD

How it occurs Tay-Sachs is a genetic mutation on the HEXA gene on the chromosome 15 (between 23 and 24) The HEXA gene’s job is to provide instructions for making one part of the enzyme beta- hexosaminidase A Beta-hexosaminidase A holds a key function in the central nervous system (spinal cord and brain)

How it occurs cont’d With this mutation, the beta- hexosaminidase A enzyme is unable to break down a fatty lipid called gangliosideGm2 The enzyme’s difficulty to break it down results in the toxic build up of gangliosideGm2 It then begins to rapidly destroy brain cells during the early growth of a child The brain is not able to develop correctly due to the lack of Hexosaminidase A and its ability to function properly

Tay-Sachs is an autosomal recessive disorder. This means that there must be two copies of the gene in order for the disease to develop. If both parents are carriers of Tay-Sachs, there is a 25% chance their child will be infected with the disease. The disease can be passed to future generations.

Phenotypic effects Babies will appear to be developing normally until about 6 months Loss of peripheral vision is an early symptom At about the age of 2, a child may have recurrent seizures and a slowing down of their mental capacity A child with TSD may also experience deafness, blindness, retardation, paralysis and ultimately death (usually around the age of 3-4 years)

Treatments As of now, there is no known treatment or cure for Tay-Sachs There have been break throughs in the exploration of “enzyme replacement therapy” This could potentially provide the baby with the HEXA that is absent Another is gene therapy, transfer of a normal gene to replace the abnormal gene

Bibliography "Tay-Sachs." National Institute of Neurological Disorders and Stroke. N.p., n.d. Web. 26 Mar Genetics Home Reasearch. N.p., n.d. Web. 26 Mar Kids Health: Tay-Sachs. N.p., n.d. Web. 26 Mar