Rachel Wells

» Warren Tay, 1881 ˃Observed symptomatic red spot in retina of eye » Bernard Sachs, 1887 ˃Described cellular changes in disease ˃Noticed high frequency of occurrence in Ashkenazi ˃Jew population

» Autosomal recessive disorder » Caused by defective gene on chromosome 15 » Occurs due to the lack of hexosaminidase A ˃Hex A helps break down gangliosides in nerve tissue

» Infantile ˃Also called “classic” ˃Most common » Juvenile ˃Produce small amounts of Hex A ˃Develop symptoms between ages 2 and 10 » Adult or Late Onset ˃Milder symptoms ˃Symptoms usually develop between adolescence and mid-30s ˃Do not lose hearing or vision

» Usually appear at 6 months to 2 years after birth » Hearing & visual problems » Loss of muscle strength » Dementia » Irritability » Loss of muscle function or paralysis » Loss of motor skills » Seizures » Slow growth » Listlessness » “Red cherry” spot in retina

» Observation of symptoms  screening ˃Usually used to determine if unaffected individual carries one copy of mutation » Prenatal testing ˃Used to determine if fetus carries two copies of mutated gene » Enzyme assay techniques ˃Detect individuals with lower levels of hexosaminidase A through blood tests » Mutation analysis ˃Polymerase chain reaction (PCR) obtained  amplify a sample of DNA and then test genetic markers to identify specific mutations

» Treatment only for alleviation of symptoms » Death usually occurs between ages 2 to 4 for infantile ˃Age 15 for Juvenile ˃Ages vary greatly for Late-Onset

» Autosomal recessive » Caused by defective gene on chromosome 15 » 3 types  no definitive cure

» “About Tay-Sachs”. Cure Tay-Sachs Foundation. Web. 7 December » “Hex A”. Genetics Home Reference. Web. 7 December » “Hexosaminidase A Deficiency”. Counsyl. Web. 7 December » “Learning About Tay-Sachs Disease”. National Human Genome Research Institute. Web. 7 December » “Tay-Sachs Disease”. Center for Jewish Genetics. Web. 7 December » “Tay-Sachs Disease”. Genetics Home Reference. Web. 7 December » “Tay-Sachs Disease”. National Tay-Sachs & Allied Diseases. Web. 7 December 2013.