Haematology - Genetic Conditions

Question 1

how is hereditary spherocytosis inherited?

Answer 1

autosomal domiant

Question 2

pathology in hereditary spherocytosis?

Answer 2

mutation in protein that gives RBC its flexibility
becomes spherocyte shape
haemolysis can occur

Question 3

Ix for hereditary spherocytosis? results?

Answer 3

Hb (low)
bilirubin (high)
LFTs (pre hepatic - no ALT/AST rise)
blood film (spherocytes)

Question 4

how is G6PDD inherited?

Answer 4

X linked

Question 5

features of G6PDD?

Answer 5

jaundice
gallstones
splenomegaly
worse in illness/drugs/broad beans

Question 6

pathology of G6PDD?

Answer 6

enzyme used in glycolysis that is not present
glutathione does not protect against reactive oxygen species
haemolytic anaemia results

Question 7

Ix for G6PDD and results?

Answer 7

G6PDD enzyme assay
bilirubin (high)
blood film (heinz bodies)

Question 8

how are thalassaemias inherited? what do they affect?

Answer 8

aut recessive

globin chain synthesis

Question 9

what is the made up of
HbA
HbA2
HbF?

Answer 9

HbA - 2 alpha, 2 beta
HbA2 - 2 alpha, 2 delta
HbF - 2 alpha, 2 gamma

Question 10

when does adult Hb take over from fetal?

Answer 10

6-12 months old

Question 11

in alpha thalassaemias , what types exist?

Answer 11

trait (a-/a-)
disease (–/-a)
hydrops fetalis (–/–)

Question 12

in beta thalassaemias , what types exist?

Answer 12

trait (B+/B) or (B0/B)
intermedia (B+/B+) or (B0/B+)
major (B0/B0)

B0 = absent 
B+ = reduced

Question 13

in alpha thalassaemias , which Hb are affected?

Answer 13

all

Question 14

in beta thalassaemias, which Hb are affected?

Answer 14

HbA

Question 15

features of alpha thalassaemias?

Answer 15

trait can be asympt
splenomegaly
jaundice
iron overload
gallstones

Question 16

features of beta thalassaemias?

Answer 16

occur 6-12 months as HbF falls
pale
fail to thrive
hepatosplenomegaly
marrow expansion (skeletal change)

Question 17

Ix for thalassaemias? results?

Answer 17

microcytic hypochromic anaemia
FBC (low Hb, low MCV)
reticulocytes (raised)
HPLC (raised HbA2 in beta)
DNA testing (alpha)

Question 18

Tx for thalassaemias?

Answer 18

transfusion

± iron chelating drugs if overload