title: Screening for C3 deficiency in newborns using microarrays.
abstract: BACKGROUND
  Dried blood spot samples (DBSS) from newborns are widely used in neonatal screening for selected metabolic diseases and diagnostic possibilities for additional disorders are continuously being evaluated. Primary immunodeficiency disorders comprise a group of more than one hundred diseases, several of which are fatal early in life. Yet, a majority of the patients are not diagnosed due to lack of high-throughput screening methods.
  
  
  RESULTS
  We have previously developed a system using reverse phase protein microarrays for analysis of IgA levels in serum samples. In this study, we extended the applicability of the method to include determination of complement component C3 levels in eluates from DBSS collected at birth. Normal levels of C3 were readily detected in 269 DBSS from healthy newborns, while no C3 was detected in sera and DBSS from C3 deficient patients.
  
  
  CONCLUSIONS
  The findings suggest that patients with deficiencies of specific serum proteins can be identified by analysis of DBSS using reverse phase protein microarrays.
authors.affiliation: Division of Clinical Immunology, Karolinska Institutet, KUS Huddinge, Stockholm, Sweden.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Janzi
authors.forename: Ronald
authors.initials: R
authors.lastname: Sjöberg
authors.forename: Jinghong
authors.initials: J
authors.lastname: Wan
authors.forename: Björn
authors.initials: B
authors.lastname: Fischler
authors.forename: Ulrika
authors.initials: U
authors.lastname: von Döbeln
authors.forename: Lourdes
authors.initials: L
authors.lastname: Isaac
authors.forename: Peter
authors.initials: P
authors.lastname: Nilsson
authors.forename: Lennart
authors.initials: L
authors.lastname: Hammarström
mesh_terms: D003176:Complement C3 / Q000032:analysis* / Q000172:deficiency*; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening / Q000379:methods; D040081:Protein Array Analysis / Q000379:methods*
chemical_list: D003176:Complement C3