Severe combined immunodeficiency (SCID) is a group of genetic disorders where the immune system is missing or not functioning properly, resulting in little to no immune response. The two most common types are X-linked SCID, caused by a mutation on the X chromosome preventing the development of T cells, and adenosine deaminase deficiency SCID, where a lack of the enzyme adenosine deaminase prevents maturation of lymphocytes. Without treatment like bone marrow transplant or gene therapy, patients with SCID develop serious infections very early in life.

1. SEVERE COMBINED
IMMUNODEFICIENCY
Submitted to: Dr Amber
Submitted by: Mahnoor Khawaja
Course : Immunology

2. Primary immunodeficiency
 Primary immuno
deficiencies are disorders in
which part of the
body's immune system is
missing or does not
function normally.
 No environmental or toxin are
involved.
 Most primary
immunodeficiency are genetic
disorders.

3. Introduction
 Severe combined
immunodeficiency
(SCID) is a group of fatal
disorder that results in
little or no immune
response. The disease is
also called ‘bubble boy’
disease.

4. Immune system
 T and B cells become non function in
SCID, which causes onset of serious
infections with early days of birth.
Pneumonia Live viruses
Blood stream
infection
Diarrhea
Oral thrush

5. Innate system
 Some elements of the innate immune system
including natural killer (NK) cells, macrophages,
granulocytes and complement proteins are active.
 NK cells are present in approximately 50 percent
of patients with SCID and may provide a degree of
protection against bacterial and viral infections in
these patients.

7. Common Types
SCID
XSCID (X
linked )
Adenosine
deaminase
(ADA)

8. XSCID
 This type of SCID is inheritable, caused by a
mutation occurring in the xq13.1 locus of the X-
chromosome.

9. Mutation
 Mutation of IL2RG protein
,causes defeat or absence of
gamma chain.
 At the end T cells are unable
to deliver the signal to B or
NK cells, which prevent
their maturation.

10. Role of interleukin
 The subunit of IL2RG causing XSCID are;
Interleukin
4,15 (B cell) Interleukin 7,

11. Cell profile

12. Adenosine deaminase (ADA)
 Adenosine
deaminase is the
enzyme that is
affected during
ADA deficiency.
 Deoxyadenosine is
accumulated as the
result of ADA.

13. Diagnosis
Complete Blood
Counts
T cell, B cell,
and NK cell
counts
Specific genetic
testing
Immunoglobulin
levels (IgG,
IgM, IgA, IgE)

14. Treatment
 Bone marrow transplant, which provides a
new immune system to the patient.
 Gene therapy treatment of SCID has also
been successful in clinical trials, but not
without complications.
 Enzyme replacement therapy.

15. Gene therapy

16. References
 http://www.bio.davidson.edu/courses/immunol
ogy/students/spring2006/kinsell/ADASCID.htm
 https://geneticmutationruebe7.wikispaces.com/
Severe+Combined+Immunodeficiency+(SCID)