Chromosome Structure

Question 1

Williams syndrome

Answer 1

90% deletion of elastin gene

Question 2

DiGeorge syndrome

Answer 2

del 22q11

Question 3

Cri-du-chat

Answer 3

terminal deletion on one arm

Question 4

Imprinting

Answer 4

normal process that silences one parent’s gene via methylation, other gene expressed

Question 5

Prader-willi

Answer 5

maternal genes silenced, paternal allele wrong

Question 6

angelman

Answer 6

paternal genes silenced, maternal allele wrong

Question 7

translocation

Answer 7

recipricol: balanced, no loss or gain, carriers are normal, high risk of miscarriage
nonreciprocal: loss or gain, abnormal carriers
robertsonian: familial DS, attaches chromsomes end to end

Question 8

Philadephia chromosome

Answer 8

reciprocal translocation of 9 and 22, one big one small

chronic myelogenous leukemia

Question 9

expanded nucleotide repeat diseases

Answer 9

huntington (AD), fragile X (XD)