Endocrine Abstracts

Introduction: An increased frequency of autoimmune diseases and an elevated incidence of autoantibodies have been observed in Turner syndrome (TS), but indirect immunofluorescence (IIF) has not been able to demonstrate autoantibodies against the adrenal cortex. We asked if the more sensitive radioimmunosorbant assay employing recombinant human 21-hydroxylase was able to identify autoantibodies against 21-hydroxylase, (21OH-Ab) in TS patients; 21-hydroxylase is the major adrenal cortex autoantigen in patients with autoimmune Addison’s disease. Moreover, TS patients were tested for antibodies against interferon omega (IFNw-Ab), a marker for autoimmune polyendocrine syndrome 1 (APS 1) where autoimmune Addison’s disease is one of the main components.

Methods: Blood samples from 144 karyotyped TS (11–62 years) were assayed 21OH-Ab and IFNw-Ab using in vitro transcribed and translated autoantigen. An index was calculated with a cut-off point of 57 and 200 for 21OH-Ab and IFNw-Ab respectively.

Results: Autoantibodies against 21-hydroxylase with low indices were present in 6 TS patients (4.2%); none had INF-omega autoantibodies. Overall, the TS patients had a mean age of 31.6 years (range 11.2–62.2). 53% (n=77) had the karyotype 45X. Hypothyroidism was recorded in 9% (n=20), coeliac disease in 1.4% (n=2), and type 1 diabetes mellitus in 0.7% (n=1). The six TS patients with 21-hydroxylase antibodies had a mean age of 32.7 years (range 17.7–44.7). Two had the karyotype 45X. One patient had hypothyroidism, but none had clinical apparent Addison’s disease.

Conclusion: 21-hydroxylase autoantibodies can be detected by using RIA in some patients with TS. These findings add to previous studies showing a high proportion of TS with an array of different autoimmune antibodies. Whether any of the autoantibody-positive TS patients will eventually develop Addison’s disease remains to be seen.