PAX9 and MSX1 transcription factor genes in non-syndromic dental agenesis.
OBJECTIVE
The molecular variation of paired domain box gene 9 (PAX9) was previously investigated by our research group and a high degree of evolutionary conservation in coding and non-coding regions was observed except in exon 3. PAX9 is a transcription factor important in tooth development, and we wanted to verify its role in dental agenesis in detail. Since dental development is a complex trait we also decided to examine the influence of another transcription factor, muscle segment homeodomain-homeobox 1 (MSX1) on it.


METHODS
A total of 360 consecutively ascertained patients seeking orthodontic treatment were screened for tooth agenesis and 33% of them were found to have it. Thirty-five of those with agenesis and 15 controls had their DNA studied for PAX9 exons 2, 3, 4 and adjacent regions (total of 1476 base pairs, bp) as well as MSX1 exon 2 (698bp). A trio (a proband and her parents) was also studied.


RESULTS
Six polymorphic sites were found, three in PAX9 exon 3 and three in MSX1 exon2. MSX1 rs1095 derived allele occurred in individuals with agenesis only, and two other mutations in this gene had been earlier associated with tooth agenesis. Homozygosity for the PAX9 Ala240Pro mutation was studied in a family (proband and her parents), suggesting recessive inheritance with variable expressivity for the dental agenesis found.


CONCLUSIONS
Common variants located out of the DNA binding domain of the two PAX9 and MSX1 genes can also be related to tooth agenesis.
Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Caixa Postal 15053, 91501-970 Porto Alegre, RS, Brazil.
Vanessa Rodrigues
VR
Paixão-Côrtes
Tatiana
T
Braga
Francisco Mauro
FM
Salzano
Karina
K
Mundstock
Carlos Alberto
CA
Mundstock
Maria Cátira
MC
Bortolini
D000848:Anodontia / Q000235:genetics*; D016022:Case-Control Studies; D005091:Exons / Q000235:genetics; D005260:Female; D006801:Humans; D051957:MSX1 Transcription Factor / Q000235:genetics*; D008297:Male; D009805:Odontogenesis / Q000235:genetics*; D051764:PAX9 Transcription Factor / Q000235:genetics*; D011110:Polymorphism, Genetic; D012016:Reference Values
D051957:MSX1 Transcription Factor; D051764:PAX9 Transcription Factor