Tay-Sachs disease (TSD) is an inherited disorder caused by deficiency of Hexosaminidase A enzyme. This enzyme is necessary to break down fatty substances in the cells of the nervous system. Accumulation of these fatty substances causes the brain and spinal cord nerve cells to malfunction. Children with TSD have normal development until about 6 months of age at which time they present with loss of motor skills, decreased attentiveness, and increased startle response. As the disease progresses, children with TSD develop deafness, blindness, paralysis, seizures, and death usually occurs by age 3-4 years. There is no treatment available for TSD. In addition to TSD other forms of Hexosaminidase A deficiencies exist. They include the juvenile (subacute), chronic, and adult onset disease. These tend to have later onset, slower course, and variable neurologic outcome. TSD is caused by pathogenic variants in the HEXA gene.