title: Purkinje cell cytoplasmic antibody type 1 (anti-Yo) autoimmunity in a child with Down syndrome.
abstract: OBJECTIVE
  Purkinje cell cytoplasmic antibody type 1 (PCA-1)-IgG (or anti-Yo) is characteristically detected in women with gynecological or breast adenocarcinoma. We describe 2 unique scenarios occurring in 1 patient: PCA-1 paraneoplastic autoimmunity in a child, and a paraneoplastic neurological disorder in the context of Down syndrome.
  
  
  METHODS
  A child with Down syndrome and a history of adrenocortical carcinoma resected at age 1 year presented at age 7 years with cerebellar ataxia of subacute onset. Paraneoplastic serological and cerebrospinal fluid evaluations revealed PCA-1. Serological and biochemical studies also supported a diagnosis of subclinical autoimmune hypothyroidism. Extensive serum, urine, and radiological testing did not reveal a new or recurrent neoplasm. Neurological improvements after standard immunotherapy were lacking.
  
  
  CONCLUSIONS
  Solid organ neoplasms are uncommon among patients with Down syndrome, but organ-specific autoimmune diseases are common. In our patient, Down syndrome-related impaired T regulatory lymphocyte function (previously reported) may have resulted in both enhanced immunity against an undetected solid neoplasm and paraneoplastic neurological (PCA-1) autoimmunity.
authors.affiliation: Department of Pediatric Neurology, Golisano Children's Hospital of Southwest Florida, Fort Myers.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Philipps
authors.affiliation: Department of Pediatric Hematology and Oncology, Golisano Children's Hospital of Southwest Florida, Fort Myers.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Alisanski
authors.affiliation: Department of Neurology, Southern Illinois University School of Medicine, Springfield.
authors.forename: Michael
authors.initials: M
authors.lastname: Pranzatelli
authors.affiliation: Department of Neurology, College of Medicine, Mayo Clinic, Rochester, Minnesota.
authors.forename: Stacey L
authors.initials: SL
authors.lastname: Clardy
authors.affiliation: Department of Neurology, College of Medicine, Mayo Clinic, Rochester, Minnesota5Department of Immunology, College of Medicine, Mayo Clinic, Rochester, Minnesota6Department of Laboratory Medicine and Pathology, College of Medicine, Mayo Clinic, Rochester.
authors.forename: Vanda A
authors.initials: VA
authors.lastname: Lennon
authors.affiliation: Department of Neurology, College of Medicine, Mayo Clinic, Rochester, Minnesota6Department of Laboratory Medicine and Pathology, College of Medicine, Mayo Clinic, Rochester, Minnesota.
authors.forename: Andrew
authors.initials: A
authors.lastname: McKeon
mesh_terms: D001323:Autoantibodies / Q000096:biosynthesis*; D001324:Autoantigens / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology; D002524:Cerebellar Ataxia / Q000453:epidemiology / Q000276:immunology / Q000473:pathology; D002648:Child; D015897:Comorbidity; D003593:Cytoplasm / Q000276:immunology* / Q000378:metabolism; D004314:Down Syndrome / Q000453:epidemiology; D005260:Female; D006801:Humans; D009419:Nerve Tissue Proteins / Q000276:immunology; D020361:Paraneoplastic Syndromes, Nervous System / Q000453:epidemiology / Q000276:immunology*; D011689:Purkinje Cells / Q000276:immunology* / Q000473:pathology
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; C063762:CDR1 protein, human; D009419:Nerve Tissue Proteins