{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:46:14Z","timestamp":1760237174071,"version":"build-2065373602"},"reference-count":30,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2020,3,10]],"date-time":"2020-03-10T00:00:00Z","timestamp":1583798400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Complement deficiencies are rare and often underdiagnosed primary immunodeficiencies that may be associated with invasive bacterial diseases. Serious infections with encapsulated organisms (mainly Streptococcus pneumoniae, but also Neisseria meningitides and Haemophilus influenzae type B) are frequent in patients with a deficiency of the second component of complement (C2), but no data are available on long-term follow-up. This study aimed to evaluate the long-term clinical outcome and the importance of an early diagnosis and subsequent infection prophylaxis in C2 deficiency. Here, we report the 21-year follow-up of a whole family which was tested for complement parameters, genetic analysis and biochemical measurements, due to recurrent pneumococcal meningitis in the elder brother. The two sons were diagnosed with homozygous type 1 C2 deficiency, while their parents were heterozygous with normal complement parameters. For the two brothers, a recommended vaccination program and antibiotic prophylaxis were prescribed. During the long-term follow-up, no severe\/invasive infections were observed in either patient. At the age of 16, the younger brother developed progressive hypogammaglobulinemia of all three classes, IgA, IgM and IgG. A next generation sequencing panel excluded the presence of gene defects related to primary antibody deficiencies. Our data show that early diagnosis, use of vaccinations and antibiotic prophylaxis may allow a normal life in hereditary C2 deficiency, which can be characterized using functional and genetic methods. Moreover, a periodical check of immunoglobulin serum levels could be useful to detect a possible hypogammaglobulinemia.<\/jats:p>","DOI":"10.3390\/medicina56030120","type":"journal-article","created":{"date-parts":[[2020,3,10]],"date-time":"2020-03-10T11:59:36Z","timestamp":1583841576000},"page":"120","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Hereditary Deficiency of the Second Component of Complement: Early Diagnosis and 21-Year Follow-Up of a Family"],"prefix":"10.3390","volume":"56","author":[{"given":"Rosa Maria","family":"Dellepiane","sequence":"first","affiliation":[{"name":"Department of Pediatrics, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, University of Milan, 20122 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lucia Augusta","family":"Baselli","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, University of Milan, 20122 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marco","family":"Cazzaniga","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico, University of Milan, 20122 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vassilios","family":"Lougaris","sequence":"additional","affiliation":[{"name":"Pediatrics Clinic and Institute for Molecular Medicine A. Nocivelli, Department of Clinical and Experimental Sciences, University of Brescia and Spedali Civili di Brescia, 25121 Brescia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3079-4019","authenticated-orcid":false,"given":"Paolo","family":"Macor","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, University of Trieste, 34123 Trieste, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mara","family":"Giordano","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Laboratory of Genetics, University of Eastern Piedmont and Interdisciplinary Research Center of Autoimmune Diseases, 28100 Novara, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6465-7624","authenticated-orcid":false,"given":"Roberta","family":"Gualtierotti","sequence":"additional","affiliation":[{"name":"Internal Medicine, Department of Pathophysiology and Transplantation, University of Milan, Fondazione IRCCS Ca\u2019 Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9918-0763","authenticated-orcid":false,"given":"Massimo","family":"Cugno","sequence":"additional","affiliation":[{"name":"Internal Medicine, Department of Pathophysiology and Transplantation, University of Milan, Fondazione IRCCS Ca\u2019 Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,3,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"965","DOI":"10.1016\/j.addr.2011.06.005","article-title":"Complement in health and disease","volume":"63","author":"Carroll","year":"2011","journal-title":"Adv. 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