Which of the following is/are accurate when describing Huntington's Disease (HD)?

a. Polyalanines are a marker
b. HD is an example of a recessive lethal allele
c. The affected phenotypes are heterozygous AND homozygous recessive
d. You would expect an individual with the genotype 'Dd' to exhibit Huntington's Disease
e. All of the above are correct
f. None of the above are correct