Clinical Research And Detection Of MSX1 Gene And PAX9 Gene To Non-syndrome Tooth Agenesis

Objective:To study characteristic and genetics mechanisms of non-syndrome tooth agenesis(NSTA),in order to provide evidence of clinical diagnose and cure this desease.Methods:18 family members(11 disease,7 normal ) in 4 family constellations of non-syndrome tooth agenesis who were final diagnosised by Department of Orthodontics,Stomatology Hospital,ZheJiang University College of Medicine from 2006 October to 2008 July were investigated.First oral cavity special examinations were performed,including shape and numerus of teeth,dentition and dental formula; Then system medical examination were performed to exclude hairs,nails or sweat glands abnormality.Oral panorama scopy to verification humerus of teeth,excluding possibility of ambushed or impacted tooth.Genetics pedigree analysis by Family surveying.Laboratory examinations of peripheral venous blood,including Chromosome analysis(autosome number,heterosome number,caryotype,numerical aberration ratio,structural aberration ratio,et al),serum microelements cuprum,zincum, ferrum,magnesium,calcium and serum alkaline phosphatase(ALP).5-10ml peripheral venous blood were collected,genome DNA were extracted from these 18 study objects and 2 healthy volunteers,then PCR were performed after 6 pairs primers were designed to 4 exons of PAX9 gene and 2 exons of MSXlgene.Gene mutation were analysised by Single Strand Conformation Polymorphism(SSCP) and DNA sequencing.Results:Patients' clinical situations were multiplicity,including number or position of missing teeth,size or shape of teeth in mouths.Tooth position of stricken teeth was selectivity,Missing rate of lateral incisor was the highest,then canines,and then premolars and second molar,first molar lowest.4 Genealogy were autosomal dominant inheritance,serum microelements cuprum,zincum,ferrum,magnesium,calcium and serum alkaline phosphatase(ALP) were mainly normal.Purity of DNA extracted was fine,PCR amplification of all gene fragments succeeded.5 of llpatients and 1 of 9 healthy members showed anormal electrophoresis of Single Strand Conformation Polymorphism.Two single nucleotide polymorphisms sites(cSNP):rs12881240 and rs4904210 in fourth exon of PAX9 gene were found.No other mutation was detected in the rest exons of PAX9 and all exons of MSX1.Conclusions:Clinical situation and mode of inheritance are variety;but the position of involved teeth(including missing teeth and distorted teeth) of non-syndrome tooth agenesisis is of selectivity,rs12881240 and rs4904210 polymorphisms of fourth exon in PAX9 gene is possible predisposing factor of non-syndrome tooth agenesis.These two single nucleotide polymorphisms sites have heredity,incorrelate each other,and mode of inheritance is autosomal dominant inheritance.