¹Department of Oral Biology, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA

Correspondence: Dr G Gallagher, Department of Oral Biology, New Jersey Dental School, 185 South Orange Avenue, MSB, Room C636, Newark, NJ 07103-2714, USA. E-mail: gallaggr@umdnj.edu

Received 15 December 2004; Revised 9 May 2005; Accepted 9 May 2005; Published online 6 October 2005.

Abstract

Lactoferrin is an antimicrobial protein which plays an important role in regulating bacteria that are associated with aggressive periodontitis. Lactoferrin kills directly (via its strongly cationic N-terminal region) and indirectly, through sequestering the iron that bacteria require for growth. As aggressive periodontitis has a strong heritable component, we hypothesized that genetic variation within the lactoferrin gene may play a role in susceptibility to this condition. We have identified and examined a novel, functional, single-point A/G nucleotide mutation causing a threonine/alanine substitution at position 11 (T11A) of the secreted lactoferrin protein. In a pilot case-controlled study of aggressive periodontitis, analysis of 46 African-American patients and 78 controls showed that patients were twice as likely to express the G nucleotide (alanine) allele over controls (60.3 vs 30.4%; P=0.0007, odds ratio=2.564, 95% CI=1.475–4.459). A Caucasian population of 77 patients and 131 controls showed no such association (P=0.5201, odds ratio=0.862, 95% CI=0.548–1.356). The data presented provide a new insight into the genetic susceptibility to aggressive periodontitis.