Evidence of a Substantial Genetic Basis for IgG2 Levels in Families with Aggressive Periodontitis

• Published in: Journal of dental research Vol. 82; no. 9; pp. 708 - 712
• Main Authors: Diehl, S.R., Wu, T., Burmeister, J.A., Califano, J.V., Brooks, C.N., Tew, J.G., Schenkein, H.A.
• Format: Journal Article
• Language: English
• Published: United States SAGE Publications 01.09.2003; SAGE PUBLICATIONS, INC
• Subjects: Adolescent; Adult; Age Factors; Aged; antibody response; Black or African American; Black People - genetics; Female; genetic correlation; Genetic Predisposition to Disease; Genetic Variation - genetics; heritability; host susceptibility; Humans; Immunoglobulin G - genetics; Male; Middle Aged; Periodontal Attachment Loss - genetics; Periodontal Attachment Loss - immunology; Periodontitis - genetics; Periodontitis - immunology; Risk Factors; Smoking - genetics; Smoking - immunology; variance components; White People - genetics; variance components; antibody response; genetic correlation; host susceptibility; heritability
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/154405910308200910

IgG2 is elevated in localized but not in generalized aggressive periodontitis (AgP). Exposure to pathogenic bacteria is essential for disease. Immune responses are dominated by IgG2 reactive with bacterial surface carbohydrates. We used variance component analyses to assess IgG2 heritability and determine whether genes that influence IgG2 are the same genes that influence disease susceptibility. We studied 17 Caucasian and 43 African American families with two or more localized or generalized AgP-affected members (274 subjects with IgG2 measurements). Only 16% of the variance in IgG2 was attributable to age, race, and smoking. Even with the addition of localized AgP, the model still explained only 19% of IgG2 variance. By contrast, heritability of IgG2 levels was estimated to be 38% and highly significant (P = 0.0006), demonstrating a substantial genetic basis. Bi-trait variance component analyses of IgG2 and quantitative measures of AgP indicate that different genes appear to control IgG2 levels and disease susceptibility.