Santos-Valente, ElisangelaReisli, İsmailArtaç, HasibeOtt, RaphaelSanal, ÖzdenBoztug, Kaan2020-03-262020-03-262012Reisli, I., Artaç, H., Ott, R., Sanal, O., Boztug, K., (2012). Identification of a Novel Mutation in the Complement Factor 3 Gene in a Patient With Recurrent Pneumococcal Pneumonia. Journal of Clinical Immunology, (33), 89-90. Doi: 10.1007/s10875-012-9775-z0271-9142https://hdl.handle.net/20.500.12395/2812215th Biennial Meeting European-Society-for-Immunodeficiency (ESID) -- OCT 03-06, 2012 -- Florence, ITALYPurpose Immunological and molecular evaluation of a pa tient presenting with recurrent infections caused by Strepto coccus pneumoniae and low complement component 3 (C3) levels. Methods Immunological evaluation included complement components and immunoglobulin level quantification as well as number and function of T cells, B cells and neutro phils. Serotype-specific immunoglobulin G antibodies against S. pneumoniae capsular polysaccharides were quan tified by ELISA in serum samples before and after vaccina tion with unconjugated polysaccharide vaccine. For the molecular analysis, genomic DNA from the patient and parents were isolated and all exons as well as exon-intron boundaries of the C3 gene were sequenced by Sanger sequencing. Results A 16-year-old male, born to consanguineous parents, presented with recurrent episodes of pneumonia caused by S. pneumoniae and bronchiectasis. The patient showed severely reduced C3 and immunoglobulin A levels, while the parents showed moderately reduced levels of C3. Mutational analysis revealed a novel, homozygous missense mutation in the C3 gene (c. C4554G, p. Cys1518Trp), substituting a highly conserved amino acid in the C345C domain of C3 and interrupting one of its disulfide bonds. Both parents were found to be carriers of the affected allele. Vaccination against S. pneumoniae resulted in considerable clinical improvement.eninfo:eu-repo/semantics/openAccessConference Object338990WOS:000308728900171Q2