The authors have no competing interests. All the authors declare that they have no involvement in or affiliations with any organization or entity with any interest, financial or otherwise in the subject matter or materials discussed in this manuscript.

This is a retrospective analysis using DNA extracted from EDTA blood sample that has been collected for routine molecular diagnostic procedures in patients with primary immunodeficiency in our institution. No additional information was gathered, nor sample collected from the patient for the purpose of this study. All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments.