SCID

Question 1

SCID is caused by a mutation in

Answer 1

Adenosine deaminase (ADA)

Question 2

Mutation in ADA is located on

Answer 2

Chromosome 20q13.12

Question 3

ADA is an essential enzyme in

Answer 3

Purine metabolism

Question 4

ADA structure

Answer 4

(B/a)8 barrael enzyme
Active sites the B/a loop
(Reardon and Farber, 1995)

Question 5

ADA catalyses

Answer 5

Hydrolysis of adenosine to 2’deoxyadenosine to inosine and 2’deoxyinosine
(Wilsom et al, 1991)

Question 6

Inosine and 2’deoxyinosine are metabolised by

Answer 6

Purine nucleoside phosphorylase (PNP)

Question 7

PNP metabolised inosine and 2’deoxyinosine to..

Answer 7

hypoxanthine which enters a non-reversible pathway to uric acid

Question 8

Highest levels of ADA activity are in the..

Answer 8

lymphoid tissues, thymus, Gi tract and the brain

Flinn and Gennery, 2018

Question 9

SCID is what type of disorder

Answer 9

Primary immunodeficiency disorder

de Vries and Drissen, 2011

Question 10

Mutation in ADA cause

Answer 10

LoF of the enzyme

Question 11

> 70 mutations in ADA have been found

Answer 11

63% missense
18% RNA splicing
13% deletions 
6% nonsense 
(Hershfield, 2013)

Question 12

LoF of ADA causes ..

Answer 12

Elevated levels of adenosine and 2’deoxyadenosine

Question 13

Elevated levels of adenosine and 2’deoxyadenosine cause

Answer 13

Accumulation of toxic metabolites e.g. dATP

Question 14

Toxic metabolites e.g. dATP prevent

Answer 14

Normal synthesis and repair of DNA and development of T lymphocytes and of B- and NK-cells
(Cagdas et al., 2018)

Question 15

Patients with SCID experience

Answer 15

Recurrent severe infections from opportunistic organisms

Question 16

85% of SCID patients show manifestations within..

Answer 16

First 6 months of life (Cagdas et al., 2018)

Question 17

Reconstitution of the immune system is..

Answer 17

Vital for survival