Novel genes linked to Class II Division 1 malocclusion with mandibular micrognathism

Introduction: Mandibular micrognathism (MM) is an underdeveloped mandible resulting from complex interac-tions between genetic and environmental factors. Prior research focused mainly on the genetic determinants of mandibular retrognathism, not necessarily reflecting micrognathism, thus supporting the need to study MM. This study aimed to explore the inheritance pattern and identify the candidate genes involved in the development and familial transmission of MM. Methods: Diagnosing probands with MM was based on clinical and lateral cepha-lometric data. The pedigrees were drawn for 11 identified families, 5 of whom accepted to undergo detailed data and biospecimen collection. These families included 15 MM and 13 non-MM subjects over 2-3 generations. The procedure involved the withdrawal of 5 mL of blood. Genomic DNA was isolated from blood cells to investigate protein-coding regions via whole exome sequencing. Standardized filtering steps were employed, and candidate genes were identified. Results: Most of the pedigrees suggested a Mendelian inheritance pattern and segre-gated in an autosomal-dominant manner. One of the families, which also underwent biospecimen, displayed an X-linked inheritance pattern of the trait. Genetic screening disclosed 8 potentially novel genes (GLUD2, ADGRG4, ARSH, TGIF1, FGFR3, ZNF181, INTS7, and WNT6). None of the recognized exonic regions were previously reported. Conclusions: Eight novel genes were identified in association with MM in the largest num-ber of families reported to date. The genes were X-linked in 1 family, a finding previously not observed in mandib-ular genetics. (Am J Orthod Dentofacial Orthop 2023;163:667-76)