Genetic Association Analysis of CYP19A1 in Pubertal Sagittal Facial Growth

Objective: Current methods of facial growth prediction tend to incorporate growth measurements taken earlier in a patient’s life which are then used in conjunction with predetermined norms to estimate a patient’s future growth.  As useful as these facial growth predictions are, however, a more accurate prediction would take into account the unique genetics of each individual patient. The CYP19A1 gene encodes the aromatase enzyme which catalyzes estrogen biosynthesis via the conversion of androgens. The androgen/estrogen ratio affects the difference in development of male and female facial characteristics. Genetic variation in CYP19A1 has been associated with different average sagittal facial growth during puberty in Chinese males. Our null hypothesis (H_O) was that the single nucleotide polymorphisms (SNPs) rs2470144, rs2445761 and rs730154, located within in the CYP19A1 gene, are not associated with variation in average sagittal jaw growth during puberty in Caucasians.  

Method: Genotypes for rs2470144, rs2445761, and rs730154 were determined by Taqman®-based methodology in 63 subjects (30-females; 33-males) who began orthodontic treatment at cervical stages (CS) 2 or 3 and progressed to CS4 or CS5. Pre- and post-treatment lateral cephalometric radiographs were measured with Dolphin software. Pre-orthodontic measurements and annualized average changes of maxillary and mandibular sagittal lengths were compared among genotypes for each SNP by ANOVA (p≤0.05).

Result: The average annual increases of the maxillary and mandibular sagittal lengths were not significantly different (p>0.3) for females or males according to rs2470144, rs2445761, or rs730154 genotype. Therefore we could not reject our null hypothesis.

Conclusion: We did not find the same association of CYP19A1 gene variation with pubertal average sagittal facial growth in a small Caucasian sample as was found in a larger Chinese sample.  We are increasing our sample size to match the Chinese study.