Juvenile ankylosing spondylitis in Turner syndrome.

Juvenile ankylosing spondylitis (JAS) is a chronic autoimmune disorder which causes considerable morbidity when left untreated; it occurs predominantly in men. We describe an Asian Indian woman who had JAS with phenotypic features of Turner syndrome (TS) and was found to be a mosaic for 45, X/46, X, psu idic (X) (p11) by karyotyping and fluorescence in situ hybridization (FISH) studies of peripheral blood. The absence of Y chromosome material was confirmed by FISH. Haplo-insufficiency of the X chromosome can predispose to autoimmunity. To the best of our knowledge, this is the first report of JAS in association with mosaic Turner syndrome. This case highlights the possible effects of gene dosage in development of an autoimmune disease.