title: Marked variability in clinical presentation and outcome of patients with C1q immunodeficiency.
abstract: OBJECTIVE
  Globally approximately 60 cases of C1q deficiency have been described with a high prevalence of Systemic Lupus Erythematosus (SLE). So far treatment has been guided by the clinical presentation rather than the underlying C1q deficiency. Recently, it was shown that C1q production can be restored by allogeneic hematopoietic stem cell transplantation. Current literature lacks information on disease progression and quality of life of C1q deficient persons which is of major importance to guide clinicians taking care of patients with this rare disease.
  
  
  METHODS
  We performed an international survey, of clinicians treating C1q deficient patients. A high response rate of >70% of the contacted clinicians yielded information on 45 patients with C1q deficiency of which 25 are published.
  
  
  RESULTS
  Follow-up data of 45 patients from 31 families was obtained for a median of 11 years after diagnosis. Of these patients 36 (80%) suffer from SLE, of which 16 suffer from SLE and infections, 5 (11%) suffer from infections only and 4 (9%) have no symptoms. In total 9 (20%) of the C1q deficient individuals had died. All except for one died before the age of 20 years. Estimated survival times suggest 20% case-fatality before the age of 20, and at least 50% of patients are expected to reach their middle ages.
  
  
  CONCLUSIONS
  Here we report the largest phenotypic data set on C1q deficiency to date, revealing high variance; with high mortality but also a subset of patients with an excellent prognosis. Management of C1q deficiency requires a personalized approach.
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Rosanne A
authors.initials: RA
authors.lastname: van Schaarenburg
authors.affiliation: Department of Clinical Immunology, Laboratory of Molecular Medicine, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Lone
authors.initials: L
authors.lastname: Schejbel
authors.affiliation: Department of Laboratory Medicine, Section of Microbiology, Immunology and Glycobiology, Lund University, Lund, Sweden.
authors.forename: Lennart
authors.initials: L
authors.lastname: Truedsson
authors.affiliation: Dept of Pediatric Nephrology and Rheumatology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Rezan
authors.initials: R
authors.lastname: Topaloglu
authors.affiliation: Pediatric Rheumatology Department, King Faisal Specialist Hospital & Research Center, Alfaisal University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Sulaiman M
authors.initials: SM
authors.lastname: Al-Mayouf
authors.affiliation: Alder Hey Children's NHS Foundation Trust, Liverpool, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Riordan
authors.affiliation: Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Anna
authors.initials: A
authors.lastname: Simon
authors.affiliation: La Rabta Hospital, Tunis, Tunisia.
authors.forename: Maryam
authors.initials: M
authors.lastname: Kallel-Sellami
authors.affiliation: University of Manchester, Manchester, United Kingdom.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Arkwright
authors.affiliation: Department of Clinical Science and Education, Sachs' Children's Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Åhlin
authors.affiliation: Department of Clinical Science and Education, Sachs' Children's Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hagelberg
authors.affiliation: Pediatric Rheumatology Rigshospitalet, Copenhagen, Denmark.
authors.forename: Susan
authors.initials: S
authors.lastname: Nielsen
authors.affiliation: Department of Dermatology and Venereology Umeå University, Umeå, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Shayesteh
authors.affiliation: Nephrology Unit from Hospital Dr Molina Orosa. Ctra. Arrecife-Tinajo, Lanzarote, Spain.
authors.forename: Adelaida
authors.initials: A
authors.lastname: Morales
authors.affiliation: Asthma & Allergy Clinic of Marin & San Francisco Inc, San Francisco, USA.
authors.forename: Schuman
authors.initials: S
authors.lastname: Tam
authors.affiliation: Dr Behcet Uz Children's Hospital, Izmir/Konak, Turkey.
authors.forename: Ferah
authors.initials: F
authors.lastname: Genel
authors.affiliation: Pediatric Immunology, The Queen Silvia Children's Hospital, Goteborg, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Berg
authors.affiliation: Department of Pediatrics, Spaarne Hospital, Hoofddorp, The Netherlands.
authors.forename: Arnoldus G
authors.initials: AG
authors.lastname: Ketel
authors.affiliation: Emma Children's Hospital, Academic Amsterdam Medical Center (AMC), Dept of Pediatric Hematology, Immunology and Infectious Disease, University of Amsterdam (UvA), Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Merlijn van den Berg
authors.affiliation: Emma Children's Hospital, Academic Amsterdam Medical Center (AMC), Dept of Pediatric Hematology, Immunology and Infectious Disease, University of Amsterdam (UvA), Amsterdam, The Netherlands.
authors.forename: Taco W
authors.initials: TW
authors.lastname: Kuijpers
authors.affiliation: Centre for Allogeneic Stem Cell Transplantation, Karolinska University Hospital, Sweden; Division of Therapeutic Immunology, Department of Laboratory Medicine, Karolinska Institutet, Sweden; Centre for Clinical Research Sörmland, Uppsala University, Sweden.
authors.forename: Richard F
authors.initials: RF
authors.lastname: Olsson
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Tom W J
authors.initials: TW
authors.lastname: Huizinga
authors.affiliation: Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Arjan C
authors.initials: AC
authors.lastname: Lankester
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: L.A.Trouw@lumc.nl.
authors.forename: Leendert A
authors.initials: LA
authors.lastname: Trouw
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D015922:Complement C1q / Q000172:deficiency* / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007239:Infections / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000628:therapy; D053208:Kaplan-Meier Estimate; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics / Q000276:immunology* / Q000628:therapy; D008297:Male; D010641:Phenotype; D011379:Prognosis; D011788:Quality of Life; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015922:Complement C1q
keywords: Autoimmunity; C1q deficiency; Infections; Systemic lupus erythematosus