A Variety of Alu-Mediated Copy Number Variations Can Underlie IL-12Rβ1 Deficiency.
Rosain J, Oleaga-Quintas C, Deswarte C, Verdin H, Marot S, Syridou G, Mansouri M, Mahdaviani SA, Venegas-Montoya E, Tsolia M, Mesdaghi M, Chernyshova L, Stepanovskiy Y, Parvaneh N, Mansouri D, Pedraza-Sánchez S, Bondarenko A, Espinosa-Padilla SE, Yamazaki-Nakashimada MA, Nieto-Patlán A, Kerner G, Lambert N, Jacques C, Corvilain E, Migaud M, Grandin V, Herrera MT, Jabot-Hanin F, Boisson-Dupuis S, Picard C, Nitschke P, Puel A, Tores F, Abel L, Blancas-Galicia L, De Baere E, Bole-Feysot C, Casanova JL, Bustamante J.
Source : J. Clin. Immunol.
2019 Oct 15
Pmid : 29995221
METHODS: We studied six MSMD patients from five unrelated kindreds displaying adverse reactions to BCG vaccination. Three of the patients also presented systemic salmonellosis, two had mucocutaneous candidiasis, and one had disseminated histoplasmosis. We searched for CNVs and other variations by IL12RB1-targeted next-generation sequencing (NGS).
RESULTS: We identified six new IL-12Rβ1-deficient patients with a complete loss of IL-12Rβ1 expression on phytohemagglutinin-activated T cells and/or EBV-transformed B cells. The cells of these patients did not respond to IL-12 and IL-23. Five different CNVs encompassing IL12RB1 (four deletions and one duplication) were identified in these patients by NGS coverage analysis, either in the homozygous state (n = 1) or in trans (n = 4) with a single-nucleotide variation (n = 3) or a small indel (n = 1). Seven of the nine mutations are novel. Interestingly, four of the five CNVs were predicted to be driven by nearby Alu elements, as well as the two previously reported large deletions. The IL12RB1 locus is actually enriched in Alu elements (44.7%), when compared with the rest of the genome (10.5%).
CONCLUSION: The IL12RB1 locus is Alu-enriched and therefore prone to rearrangements at various positions. CNVs should be considered in the genetic diagnosis of IL-12Rβ1 deficiency.