Clinical and genetic aspects of generalized aggressive periodontitis in families of Tumkur district of Karnataka, India

Abstract

Aggressive periodontitis (AP) is a complex disease whose phenotype is determined by genetic and environmental influences on the affected individuals. About 45% of the adult population in India has periodontitis. In Tumkur district of Karnataka, India, consanguineous first cousin and uncle-niece marriages are common, with a high incidence of AP. These discrepancies in the expression of periodontal disease directed us to find genetic etiology with respect to the Tumkur population. The clinical and genetic aspects of AP from this area have been presented in this paper. A total of nine families were ascertained at the Department of Periodontics, Sri Siddhartha Dental College and Hospital (Sri Siddhartha University), Tumkur. The clinical and radiographic data were gathered according to 1999 Consensus Classification of Periodontal Diseases. Peripheral blood samples were collected for total genomic DNA isolation using a Wizard TM Genomic Purification Kit (Promega, USA). The homozygosity mapping was carried out in a large consanguineous family to map a novel locus using autosomal markers from the CHLC/Weber Human Screening Set 10 (Research Genetics Inc., USA) at Indian Institute of Sciences, Bangalore. The pedigree analysis suggested that the disorder is segregating as an autosomal trait. The homozygosity mapping failed to identify a locus for generalized AP in the family. The disorder may not be segregating as an autosomal recessive trait and we could have been misled by consanguinity in the family. It could be a multifactorial trait, or it could be still segregating as an autosomal recessive trait, but the region of homozygosity could be small and we failed to detect it using microsatellite markers. Therefore, SNP-marker-based analysis is warranted in future.