"Heritability of  airway structure variables in twins with completed active growth"

Background: To evaluate the genetic and environmental influences on craniofacial and airway dimensions using cephalometric analysis and deoxyribonucleic acid (DNA) based zygosity determination in a group of post-pubertal twins. Materials: and methods: 22 cephalometric variables of 94 pairs of twins with completed growth were analysed. Zygosity was determined using 15 specific DNA markers. A genetic analysis was performed using maximum likelihood genetic structural equation modelling (GSEM). Results: : The genetic heritability estimates of cephalometric variables describing upper airway dimensions, skeletal variables, soft palate size, maxilla relationship with hyoid bone, sagittal position of mandible. The lower airway parameters were determined by environmental factors. Conclusions: The upper airway dimensions are strongly determined by genes while the lower airway parameters are affected by environmental factors. Trial registration: The protocol has been approved by the Kaunas Regional Ethical Committee No BE – 2-41., 2020 May 13.