Exploratory Associations of Targeted Genetic Variants with Cephalometric Airway Parameters in Children with Skeletal Class II Sleep-Disordered Breathing Symptoms.

Background/Objectives: Pediatric sleep-disordered breathing (SDB) is influenced by craniofacial morphology and host susceptibility. Evidence integrating cephalometric airway features with targeted genetic variation in symptomatic skeletal Class II children remains limited. We explored whether children with skeletal Class II mandibular retrognathia and SDB symptoms harbor selected genetic variants and whether carriers show distinct cephalometric airway characteristics. Methods: This cross-sectional study included 48 children with skeletal Class II malocclusion, mandibular retrognathia, and snoring/mouth-breathing symptoms. Craniofacial and airway parameters were assessed on lateral cephalograms. SDB burden was evaluated by a baseline home sleep study (respiratory event index, REI). Targeted sequencing screened TNFRSF1A, PSTPIP1, SLC6A4 (5HTT), ACE, APOE, IRS1, and additionally PHOX2B and PMP22. Exploratory group comparisons used Student's t-test. Results: Variants were identified in 13/48 participants (27%) in TNFRSF1A, PSTPIP1, SLC6A4, ACE, APOE, and IRS1; none were detected in PHOX2B or PMP22. C3-H was higher in variant carriers (39.90 ± 6.40 vs. 36.48 ± 3.95 mm; p < 0.05). HH1 (perpendicular distance from the hyoid bone to the C3-RGN line) was higher but not significant (16.99 ± 7.58 vs. 14.61 ± 5.25 mm; p > 0.05). Conclusions: In this clinically screened pediatric skeletal Class II cohort with SDB symptoms, selected genetic variants co-occurred with specific hyoid-cervical cephalometric features. Given the cross-sectional design, absence of a control group, and small number of carriers, findings are exploratory and require replication in larger, controlled cohorts with standardized phenotyping.