of transcription the gene expressed in tooth mesenchyme at the bud stage during tooth development. A study showed that single nucleotide polymorphisms in PAX9 were highly associated with missing upper lateral incisors. AXIN2 The AXIN2 (AXIS inhibition protein 2) gene is a negative regulator of the Wnt signalling pathway, which is important in regulating cell fate, proliferation, differentiation and apoptosis. Its polymorphic variant may be associated with hypodontia such as missing lower incisors or in a more severe form of agenesis like oligontia (lack of six or more permanent teeth). EDA EDA provides instructions for making a protein called ectodysplasin A. It encodes transmembrane protein that is part of TNF (tumour necrosis factor) family of ligands. EDA gene defects cause ectodermal dysplasia, which is also known as X-linked hypohidrotic ectodermal dysplasia. Common dental features of ectodermal dysplasia are multiple missing teeth and microdontia. PAX9 and TGFA are involved in regulating between MSX1 and PAX9, causing hypodontia of the molars. Hypodontia can be found in isolated cases too. The familiar or sporadic type of isolations are more frequently reported than the syndromic type. Isolated cases of autosomal dominant, autosomal recessive, or X-linked inheritance patterns may have an impact on the isolation conditions in expressing variation of both penetration and expressivity of traits. Mutations in MSX, PAX9 and TGFA genes are known to cause congenitally missing teeth in some racial groups. Research In the 1960s and 1970s, several studies were conducted sponsored by the U.S. Atomic Energy Commission, with the aim of finding a link between genetics and hypodontia. Impact There are numerous studies and research reports on the prevalence, aetiology, and treatment of hypodontia and the dentoskeletal effect of hypodontia. A few studies have investigated Oral Health-related Quality of Life (OHRQoL) in individuals with hypodontia and provided some evidence that hypodotia may have an impact on quality of life. Psychosocial Cosmetic dentistry has become more notable and prevalent in modern society. Interpersonal relationships and perceived qualities, such as intelligence, friendliness, social class, and popularity can be affected by dentofacial appearance. Some studies have shown that the extent of complaints made by patients was associated with the severity of the condition and the number of missing permanent teeth. Meta-analyses and theoretical reviews have demonstrated that attractive children are seen by others as more intelligent and exhibit more positive social behaviour and traits, other than receiving much more positive treatment than their less