Large granular lymphocytic leukemia complicating autoimmune polyglandular syndrome type 1 in siblings.

Autoimmune polyglandular syndrome type 1 (APS1) is a rare autosomal recessive disorder, and large granular lymphocytic leukemia (LGLL) may, even more rarely, complicate APS1. LGLL may be subtle in presentation, but it is imperative to recognize LGLL in APS1 promptly, as outcome may otherwise be fatal, as described herein.