title: Autoimmune Lymphoproliferative Syndrome: A Rare Cause of Disappearing HDL Syndrome.
abstract: The term disappearing HDL syndrome refers to development of severe high density lipoprotein cholesterol (HDL-C) deficiency in noncritically ill patients with previously normal HDL-C and triglyceride levels. Autoimmune lymphoproliferative syndrome (ALPS) is a disorder of the immune system due to an inability to regulate lymphocyte homeostasis resulting in lymphadenopathy and hepatosplenomegaly. We describe a 17-year-old boy who was evaluated in the lipid clinic for history of undetectable or low HDL-C and low density lipoprotein cholesterol (LDL-C) levels. Past medical history was significant for ALPS IA diagnosed at 10 years of age when he presented with bilateral cervical adenopathy. He was known to have a missense mutation in one allele of the FAS protein extracellular domain consistent with ALPS type 1A. HDL-C and LDL-C levels had been undetectable on multiple occasions, though lipids had not been measured prior to the diagnosis of ALPS. He had been receiving sirolimus for immunosuppression. The HDL-C and LDL-C levels correlated with disease activity and improved to normal levels during times when the activity of ALPS was controlled. This case highlights the importance of considering ALPS as a cause of low HDL-C and LDL-C levels in a child with evidence of lymphoproliferation.
authors: Division of Pediatric Endocrinology, Mayo Clinic, Rochester, MN 55902, USA.
authors: Swetha
authors: S
authors: Sriram
authors: Division of Pediatric Allergy and Immunology, Mayo Clinic, Rochester, MN 55902, USA.
authors: Avni Y
authors: AY
authors: Joshi
authors: Division of Pediatric Hematology-Oncology, Mayo Clinic, Rochester, MN 55902, USA.
authors: Vilmarie
authors: V
authors: Rodriguez
authors: Division of Pediatric Endocrinology, Mayo Clinic, Rochester, MN 55902, USA.
authors: Seema
authors: 0000-0001-8004-4924
authors: S
authors: Kumar