tay sachs disease

Question 1

describe Tay Sachs disease

Answer 1

a disorder of lipid metabolism

- inherited in an autosomal recessive pattern

Question 2

what is Tay Sachs caused by?

Answer 2

a mutation in the Hexa gene that codes for the enzyme beta-hexosaminidase

Question 3

what does the enzyme beta-hexosaminidase do?

Answer 3

responsible for the breakdown of toxic substances

Question 4

what happens due to the missing enzyme?

Answer 4

accumulation of GM2 ganglioside in NS which destroys neurons

Question 5

what is the result of Tay Sachs disease?

Answer 5

intellectual + physical disabilities

death

Question 6

who is affected by Tay Sachs?

Answer 6

Jewish communities from Eastern Europe

Question 7

why are the Jewish communities affected?

Answer 7

• Genetic drift – small, isolated populations

- Heterozygotes have an advantage against TB = Jews are forced to live in areas where TB is prevalent

Question 8

what is the heterozygous advantage for Tay Sachs?

Answer 8

• reduced amount of beta-hexosaminidase = protection against tuberculosis
• survive tuberculosis + reproduce = pass on both alleles

Question 9

what happens if the patient is homozygous recessive?

Answer 9

• die before reproducing (due to tay sachs)

- does not pass on recessive allele

Question 10

what happens if the patient is homozygous dominant?

Answer 10

affected by TB + may die before reproducing