Sarge 4-9 Anemias Thalessemias

Question 1

why are there high frequencies of certain anemia in parts of the world

Answer 1

malaria infection advantage for sickle cell, isolated populations

Question 2

thalassemia

Answer 2

globin proteins quantities are low but the structure is normal, usually have nonsense or splice site mutations

Question 3

sickle cell anemia

Answer 3

Glu6Val (E6V) mutation on beta chain, hemoglobin forms chains, stick in capillaries

Question 4

heterozygote advantage

Answer 4

selective sickling of infected cells (AS red cells), phagocytosis of sickle cells

Question 5

thalassemia phenotype

Answer 5

anemia, misshapen blood cells, spleonmegaly, large bones (facial)

Question 6

cryptic splice site

Answer 6

new splice sites created by mutation in intron, may lead to stop codon inclusion. May be prevented from being used with an antisense oligonucleotide

Question 7

when do sickle cell trait people show symptoms

Answer 7

heterozygotes can suffer sickle cell trait at low oxygen, high altitude

Question 8

structure of hemoglobin

Answer 8

HbA: 2 beta units 2 alpha, heme groups in each subunit, many alpha helices

Question 9

describe genomic features of hemoglobin

Answer 9

2alpha and 1beta subunits are on different chr, in cluster of related genes in order of expression. Under control of locus control regulator (LCR-beta), and HS-40 (alpha)

Question 10

order of expression of Hb during development

Answer 10

zeta/eta until 6 weeks pregnant, then alpha/gamma until 6 months after birth (changes to regular alpha/beta)

Question 11

alpha thalassemia defect

Answer 11

loss of alpha-globin alleles (usually not just point mutations)

Question 12

beta0 thalassemia defect

Answer 12

no synthesis from an allele of beta-globin

Question 13

beta+ thalassemia defect

Answer 13

intermedia= B+/B+, B0/B+, minor= B+/B reduced synthesis from an allele of beta-globin