Polymorphisms of the noggin gene and mandibular micrognathia: a first approximation.

Mandibular micrognathia is a deficiency in mandibular growth that prevents tooth contact during mastication, interferes with phonation and even causes sleep apnea. Studies show that mutant mice for chd (chordin) and nog (noggin) genes, which are modulators of the Bone Morphogenic Protein (BMP), had mandibular defects ranging from mandibular hypoplasia to micrognathia and agnathia. The human NOG gene was the first BMP antagonist identified and it is essential for various late events in mandibular development, which require modulation of the BMP activity. The aim of this work was to determine the presence of NOG gene polymorphisms in families with mandibular micrognathia and analyze its phenotype. Four families with mandibular micrognathia were included in this study. Blood samples were taken from the participating individuals through venipuncture and DNA was extracted. The fragments of interest were amplified using the Polymerase Chain Reaction (PCR) and the Single Nucleotide Polymorphisms (SNPs) of the NOG gene reported in the NCBI data base were analyzed through direct sequencing. The SNP rs1348322 was present in homozygote form in the subjects from all the families, where Cytosine is changed to Adenine in position 112 of the exon of the NOG gene. The SNP rs1236187 did not show any clear result. This result suggests that there may be population polymorphism, or markers that are seldom polymorphic for our population. It is therefore necessary to continue with the search for the relationship of the NOG gene with mandibular micrognathia.