Impact of genetics on the position of hyoid bone

Abstract

Aim: The purpose of this study was to estimate the importance of heredity in the position of the hyoid bone. Materials and methods: lateral cephalograms of 94 same-gender twins with completed growth were analysed. The determination of zygosity was performed by means of DNA tests with polymerase chain reaction for the amplification of short tandem repeats and 15 specific DNA markers. Data were estimated by the relative influence of additive genetic factors (A), non-additive genetic factors (D), the common or shared environment (C), and unique environmental factors (E). Statistical analyses were performed with the statistical computing environment R (version 3.3.0). Results: the genetic analysis showed that the best-fitting model for the maxilla relationship with hyoid bone for linear measurements: The most posterior point of the hard palate and anterior hyoid the most anterior and superior point on the body of the hyoid bone representing the inferior part of tongue (PNS- AH) and the most anterior point of the anterior nasal spine with AH (ANS- AH ) was AE (additive genetic factors and unique environmental factors). The distance between the point of intersection of posterior pharyngeal wall and extension of second cervical vertebra lower edge line (PCV ) and AH showed common and specific environment dependency (CE). Conclusions: Genetic factors play a key role in the position of hyoid bone with maxilla. While hyoid position representing lower airway parameters with posterior pharyngeal wall was determined by environmental factors.