A novel non-stop mutation in MSX1 causing autosomal dominant non-syndromic oligodontia.

[oligodontia]

Oligodontia , which is the congenital absence of six or more permanent teeth , excluding the third molars , may contribute to masticatory dysfunction , speech alteration , aesthetic problems and malocclusion . Msh homeobox 1 (MSX 1 ) was the first gene identified as causing non-syndromic oligodontia . In this study , we identified a novel heterozygous non-stop mutation (c .910 _911 dupTA , p .*304 Tyrext *48 ) in MSX 1 in a Chinese family with autosomal dominant non-syndromic oligodontia . This novel mutation substitutes the stop codon with a tyrosine residue , potentially adding 48 amino acids to the C-terminus of MSX 1 . Further in vitro study found that mutant MSX 1 could be expressed but had lost its ability to enter the nucleus . This is the first report indicating that a non-stop mutation in MSX 1 is responsible for oligodontia . This study broadens the mutation spectrum for MSX 1 and provides a new way to clarify the mechanism of MSX 1 in tooth agenesis .