title: Severe combined immunodeficiency (SCID) in Canadian children: a national surveillance study.
abstract: OBJECTIVE
  Severe Combined Immune Deficiency (SCID) is universally fatal unless treated with hematopoietic stem cell transplantation (HSCT). Following the identification of disseminated Bacille Calmette-Guérin (BCG) infections in Canadian First Nations, Métis and Inuit (FNMI) children with unrecognized primary immune deficiencies, a national surveillance study was initiated in order to determine the incidence, diagnosis, treatment and outcome of children with SCID in Canada.
  
  
  METHODS
  Canadian pediatricians were asked to complete a monthly reporting form if they had seen a suspected SCID case, from 2004 to 2010, through the Canadian Paediatric Surveillance Program (CPSP). If the case met CPSP SCID criteria, more detailed data, including demographics and clinical information about investigations, treatment and outcome was collected.
  
  
  RESULTS
  A total of 40 cases of SCID were confirmed for an estimated incidence of SCID in non-FNMI Canadian children of 1.4 per 100,000 live births (95 % CI 1 to 1.9/100,000). The proportion of SCID cases that were FNMI (17.5 %) was almost three times higher than was expected on the basis of proportion of the pediatric population estimated to be FNMI (6.3 %) resulting in an estimated incidence of 4.4 per 100,000 live births (95 % CI 2.1 to 9.2/100,000) in FNMI Canadian children. The mean age at diagnosis for all SCID cases was 4.2 months (range 1–583 days). There were 12 deaths (30 %; 95 % CI 18–46 %); seven died of confirmed or suspected infections before they could receive an HSCT.
  
  
  CONCLUSIONS
  The frequency of SCID cases in FNMI children is higher than in the general Canadian pediatric population. The high mortality rate, due primarily to infection, suggests that early diagnosis by newborn screening followed by HSCT could significantly benefit children with SCID.
authors.forename: Jacob
authors.initials: J
authors.lastname: Rozmus
authors.forename: Anne
authors.initials: A
authors.lastname: Junker
authors.forename: Melanie Laffin
authors.initials: ML
authors.lastname: Thibodeau
authors.forename: Danielle
authors.initials: D
authors.lastname: Grenier
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Turvey
authors.forename: Wadieh
authors.initials: W
authors.lastname: Yacoub
authors.forename: Joanne
authors.initials: J
authors.lastname: Embree
authors.forename: Elie
authors.initials: E
authors.lastname: Haddad
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Langley
authors.forename: Rose Marie
authors.initials: RM
authors.lastname: Ramsingh
authors.forename: Veeran-Anne
authors.initials: VA
authors.lastname: Singh
authors.forename: Richard
authors.initials: R
authors.lastname: Long
authors.forename: Kirk R
authors.initials: KR
authors.lastname: Schultz
mesh_terms: D001500:BCG Vaccine / Q000008:administration & dosage; D002170:Canada / Q000453:epidemiology; D002675:Child, Preschool; D015331:Cohort Studies; D003937:Diagnosis, Differential; D015316:Genetic Therapy; D006801:Humans; D015994:Incidence; D007223:Infant; D016511:Severe Combined Immunodeficiency / Q000453:epidemiology* / Q000276:immunology* / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D001500:BCG Vaccine