Author Contributions: The first 2 authors, Dr Grunebaum and Dr Mazzolari, contributed equally. Dr Roifman had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Grunebaum, Porta, Notarangelo, Roifman.
Acquisition of data: Grunebaum, Mazzolari, Porta, Dallera, Atkinson, Reid, Notarangelo, Roifman.
Analysis and interpretation of data: Grunebaum, Mazzolari, Porta, Reid, Notarangelo, Roifman.
Drafting of the manuscript: Grunebaum, Mazzolari, Dallera, Reid, Notarangelo, Roifman.
Critical revision of the manuscript for important intellectual content: Grunebaum, Mazzolari, Porta, Atkinson, Reid, Notarangelo, Roifman.
Statistical analysis: Grunebaum, Notarangelo.
Obtained funding: Notarangelo, Roifman.
Administrative, technical, or material support: Mazzolari, Dallera.
Study supervision: Grunebaum, Mazzolari, Porta, Notarangelo, Roifman.
Financial Disclosures: None reported.
Funding/Support: Mutation analysis performed by Dr Notarangelo was partially supported by the Nocivelli Foundation. The MIUR-FIRB (grant RBNE01899JJ-003 to Dr Notarangelo) partially supported mutation analysis in infants with T− B+ SCID and the AFM-Telethon (grant GATA0203 to Dr Notarangelo) partially supported mutation analysis in infants with T− B− SCID. The European Union (EURO-POLICY-PID grant 006411) and the MIUR-COFIN 2004 to Dr Notarangelo partially supported data collection. In addition, the Audrey and Donald Campbell Chair of Immunology, University of Toronto, provided partial salary support for Dr Roifman. The Canadian Immunodeficiency Society partially supported data collection at the Hospital for Sick Children and the Jeffrey Modell Foundation partially supported the molecular analysis.
Role of the Sponsors: The sources of support for this study had no role in the design and conduct of the study, collection, management, analysis, and interpretation of the data, or preparation, review, or approval of the manuscript.