21 Hydroxylase Antibodies |
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Addison's disease, or primary adrenal insufficiency, is most commonly caused by autoimmune destruction of the adrenal cortex and is characterized by the presence of adrenal cortex autoantibodies in the serum. Addison's disease can occur sporadically or in combination with other autoimmune endocrine diseases, that together comprise Type I or Type II autoimmune polyglandular syndrome (APS).
The microsomal enzyme, 21-hydroxylase, is the primary antigen associated with Addison's disease. Antibodies to 21-Hydroxylase antibodies are the best marker of autoimmune Addison's disease, whether it presents alone, or as part of Type I or
Type II APS. Testing for this antibody may be useful in the investigation of adrenal insufficiency and may also aid in the detection of those at risk of developing autoimmune adrenal failure in the future.
| Patient Group |
Positive Rate |
| Healthy blood donors |
6/243 |
| Isolated Addison's disease |
43/60 |
| Addison's disease due to tuberculosis |
0/9 |
| APS type I |
11/12 |
| APS type II |
27/27 |
| Insulin dependent diabetes mellitus |
4/150 |
| Non-insulin dependent diabetes mellitus |
0/32 |
| Grave's disease |
1/77 |
| Hashimoto's disease |
1/67 |
| Myasthenia gravis |
0/35 |
| Normals from Mayo NV Study |
1/50 |
| + Insulin Antibody |
0/5 |
| + Thyroid stimulating Immunoglobin |
0/5 |
| + Anti-nuclear Antibodies |
0/10 |
| + Rheumatoid Factor |
0/10 |
Reference range is < 1U/mL. Positive results (>or=1 U/mL) indicate the presence of adrenal autoantibodies consistent with Addison's disease.
Specimen requirement is a plain red top tube of blood.
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