Polymorphism in the MSX1 gene in a family with upper lateral incisor agenesis

The MSX1 gene plays a key role in odontogenesis regulation, particularly during early stages. Since only a few genetic variants have thus far been associated with non-syndromic tooth agenesis, we screened for mutations in this gene, aiming to detect a relationship between genotype and phenotype.

The sample consisted of one proband with non-syndromic hypodontia involving upper lateral incisors, three relatives and ten unaffected controls. The proband and two affected relatives showed the same phenotype. DNA was extracted from buccal epithelial cells, and direct sequencing was performed. The two exons of MSX1 were first sequenced in the proband. When an alteration was detected, his relatives were investigated by the same method.

We identified the known polymorphism *6C>T in the homozygous state in all three affected family members. The unaffected father was heterozygous and ten control samples were negative for the *6C>T polymorphism.

The *6C>T polymorphism, when homozygous, may contribute to agenesis of upper lateral incisors. However, since the *6C>T polymorphism is quite common, additional genes must be involved in this phenotype.