Causes of Severe Combined Immunodeficiency

Causes

SCID is caused by defects in different genes involved in the development and function of infection-fighting immune cells. More than a dozen genes have been implicated in SCID, but gene defects are unknown in approximately 15 percent of newborn-screened SCID infants.

Source: NIAID (NIH)¹

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Back to: « Severe Combined Immunodeficiency

Back to: « Combined Immunodeficiency

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Severe Combined Immunodeficiency (SCID) Causes

SCID is caused by defects in different genes involved in the development and function of infection-fighting immune cells. More than a dozen genes have been implicated in SCID, but gene defects are unknown in approximately 15 percent of newborn-screened SCID infants, according to an NIH-funded study.

Most often, SCID is inherited in an autosomal recessive pattern, in which both copies of a particular gene—one inherited from the mother and one from the father—contain defects. The best-known form of autosomal recessive SCID is caused by adenosine deaminase (ADA) deficiency, in which infants lack the ADA enzyme necessary for T-cell survival.

X-linked SCID, which is caused by mutations in a gene on the X chromosome, primarily affects male infants. Boys with this type of SCID have lymphocytes that grow and develop abnormally. As a consequence, they have low numbers of T cells and natural killer cells, and their B cells do not function.

Source: NIAID (NIH)²

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Caused by defects in any of several possible genes, SCID makes those affected highly susceptible to life-threatening infections by viruses, bacteria and fungi.

Source: NHGRI (NIH)³

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In severe combined immunodeficiency, lack of an enzyme means that toxic waste builds up inside immune system cells, killing them and thus devastating the immune system.

Source: NCBI, Genes and Disease (NCBI/NIH)⁴

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The defining feature of SCID, commonly known as "bubble boy" disease, is a defect in the specialized white blood cells (B- and T-lymphocytes) that defend us from infection by viruses, bacteria and fungi.

Source: NCBI, Genes and Disease (NCBI/NIH)⁵

Causes of Severe Combined Immunodeficiency

Causes of the condition may include:⁶ Causes of Severe Combined Immunodeficiency:

• Achondroplasia, So-Called, And Severe Combined Immunodeficiency
• Combined Immunodeficiency Due To Partial RAG1 Deficiency
• Gastrointestinal Defects And Immunodeficiency Syndrome
• Immunodeficiency 26 With Or Without Neurologic Abnormalities
• LIG4 Syndrome
• Omenn Syndrome
• Reticular Dysgenesis
• Severe Combined Immunodeficiency
• Severe Combined Immunodeficiency, Autosomal Recessive, T Cell-Negative,B Cell-Negative, NK Cell-Negative, Due To Adenosine Deaminase Deficiency
• Severe Combined Immunodeficiency, Autosomal Recessive, T Cell-Negative,B Cell-Negative, NK Cell-Positive
• Severe Combined Immunodeficiency, Autosomal Recessive, T Cell-Negative,B Cell-Positive, NK Cell-Negative
• Severe Combined Immunodeficiency, Autosomal Recessive, T Cell-Negative,B Cell-Positive, NK Cell-Positive
• Severe Combined Immunodeficiency With Sensitivity To Ionizing Radiation
• Severe Combined Immunodeficiency, X-Linked
• Short-Limb Skeletal Dysplasia With Severe Combined Immunodeficiency
• Thumb Agenesis, Short Stature, And Immunodeficiency

Causes List for Severe Combined Immunodeficiency

Some of the possible causes of Severe Combined Immunodeficiency or similar disorders may include:⁷

• ADA-SCID (Severe combined immunodeficiency)
• Achondroplasia and Swiss type agammaglobulinemia (Severe combined immunodeficiency)
• Achondroplasia and severe combined immunodeficiency (Severe combined ...

... Full Causes List for Severe Combined Immunodeficiency »

Genetics of Severe Combined Immunodeficiency

More than 80 percent of SCID infants do not have a family history of the condition. ...Source: NIAID (NIH)⁸ ...

... More on Genetics »

Causes

See also cause information for related diseases:

• Causes of Combined immunodeficiency

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References

1. Source: NIAID (NIH): niaid.nih.gov/ diseases-conditions/ severe-combined-immunodeficiency-scid
2. Source: NIAID (NIH): niaid.nih.gov/ diseases-conditions/ scid-causes
3. Source: NHGRI (NIH): genome.gov/ 13014325/ learning-about-severe-combined-immunodeficiency-scid/ 
4. Source: NCBI, Genes and Disease (NCBI/NIH): ncbi.nlm.nih.gov/ books/ NBK22243/ 
5. Source: NCBI, Genes and Disease (NCBI/NIH): ncbi.nlm.nih.gov/ books/ NBK22254/ 
6. Source: Human Phenotype Ontology
7. Source: Algorithmically Generated List
8. Source: NIAID (NIH): niaid.nih.gov/ diseases-conditions/ severe-combined-immunodeficiency-scid

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