Replication of the association of chromosomal region 9p21.3 with generalized aggressive periodontitis (gAgP) using an independent case-control cohort.
BACKGROUND
The human chromosomal region 9p21.3 has been shown to be strongly associated with Coronary Heart Disease (CHD) in several Genome-wide Association Studies (GWAS). Recently, this region has also been shown to be associated with Aggressive Periodontitis (AgP), strengthening the hypothesis that the established epidemiological association between periodontitis and CHD is caused by a shared genetic background, in addition to common environmental and behavioural risk factors. However, the size of the analyzed cohorts in this primary analysis was small compared to other association studies on complex diseases. Using our own AgP cohort, we attempted to confirm the described associations for the chromosomal region 9p21.3.


METHODS
We analyzed our cohort consisting of patients suffering from the most severe form of AgP, generalized AgP (gAgP) (n = 130) and appropriate periodontally healthy control individuals (n = 339) by genotyping four tagging SNPs (rs2891168, rs1333042, rs1333048 and rs496892), located in the chromosomal region 9p21.3, that have been associated with AgP.


RESULTS
The results confirmed significant associations between three of the four SNPs and gAgP. The combination of our results with those from the study which described this association for the first time in a meta-analysis of the four tagging SNPs produced clearly lower p-values compared with the results of each individual study. According to these results, the most plausible genetic model for the association of all four tested SNPs with gAgP seems to be the multiplicative one.


CONCLUSIONS
We positively replicated the finding of an association between the chromosomal region 9p21.3 and gAgP. This result strengthens support for the hypothesis that shared susceptibility genes within this chromosomal locus might be involved in the pathogenesis of both CHD and gAgP.
Ernst
Florian D
FD
Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany.
Uhr
Katharina
K
Teumer
Alexander
A
Fanghänel
Jutta
J
Schulz
Susanne
S
Noack
Barbara
B
Gonzales
Jose
J
Reichert
Stefan
S
Eickholz
Peter
P
Holtfreter
Birte
B
Meisel
Peter
P
Linden
Gerard J
GJ
Homuth
Georg
G
Kocher
Thomas
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D010520:Aggressive Periodontitis / Q000235:genetics*; D016022:Case-Control Studies; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics*; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012307:Risk Factors; D044465:White People; D055815:Young Adult