IJSR - INTERNATIONAL JOURNAL OF SCIENTIFIC RESEARCH 1 Volume : 3 | Issue : 7 | July 2014 • ISSN No 2277 - 8179 Research Paper Medical Science * Dana Festila University of Medicine and Pharmacy “Iuliu Hatieganu”, Orthodontic Department, Cluj- Napoca, Romania. *Corresponding Author Mircea Ghergie University of Medicine and Pharmacy “Iuliu Hatieganu”, Orthodontic Department, Cluj- Napoca, Romania Alexandrina Muntean University of Medicine and Pharmacy “Iuliu Hatieganu”, Pediatric Dentistry Department, Cluj-Napoca, Romania ABSTRACT The aim of this study was to find genetic implication in the etiology of Class II subdivision 2 malocclusion us- ing single nucleotide polymorphism as genetic marker in two siblings with Class II subdivision 2 malocclusion, starting from the literature’s opinions regarding the inherited patterns of this anomaly. Clinical aspects knowing as being hereditary were found out after the extra oral, intraoral and radiological examination. Genomic DNA was also extracted from the buccal mu- cosa of the two siblings in order to determine their genotype. Four markers were selected from each patient, MyoH1, VDR, PAX9 and RUNX2. Genetic association was found between single nucleotide polymorphism and this malocclusion for PAX9 gene. Even though genetic analyze demonstrated the hereditary etiology of the Class II subdivision 2 malocclusion, some clinical features were different in the two siblings. Genetic Implications in Class II Subdivision 2 Malocclusion in Two Siblings. Case Report KEYWORDS : etiology, genotype, Class II subdivision 2 malocclusion INTRODUCTION Craniofacial structures are developed from complex processes of tissue interactions, cell migrations, and coordinated growth (Kouskoura et al., 2011; Nieminen et al., 2011). Among the 5500 inherited diseases known in humans, more than 700 are cranio- facial anomalies, but only in 20% of them the genetic determin- ism was proofed. (National Institute of Dental and Craniofacial Research Genetics Workgroup, 1999). Class II subdivision 2 anomaly is relatively rare and comprises 1.5% to 7% of all malocclusions found in white western popula- tion. (Steigman, Kawar & Zilberman, 1983), affecting especially the womens. (Hartsfield Jr., Morford & Otero, 2012) It consists of a unique combination of deep overbite, retro- clined incisors, Class II skeletal discrepancy, high lip line with strap-like activity of the lower lip, and active mentalis muscle. This is often accompanied by particular morphometric dental features also, such as a poorly developed cingulum on the up- per incisors and a characteristic crown root angulation. There is strong evidence for genetics as the main etiological factor in the development of Class II division 2 malocclusions, in some authors opinions. (Mossey, 1999) Other, like Ruf and Pancherz (1999) considered the etiology of this malocclusion being un- clear, or a combination between genetic and environmental fac- tors. Orthodontic treatment of this anomaly, but especially the long term stability of the results, can be difficult because of its genetic determinism. AIM The aim of this study was to demonstrate the genes implication in the etiology of Class II subdivision 2 malocclusion in two sib- lings. MATERIAL AND METHOD Two siblings with Class II subdivision 2 malocclusion, one brother, 11 years old and his sister, 17 years old were selected. Clinical and radiological examination was performed and in- herited patterns were registered. Also genomic DNA was ex- tracted from the buccal mucosa using Animal and Fungi DNA Preparation Kit (Jena BioScience). Gene fragments (Myo1H, VDR, PAX9 and RUNX2) were amplified with Polymerase Cha- in Reaction. RESULTS Case 1 – 11 years old –Class II/2. His genotype distribution was: GG for Myo1H, AA for PAX9, CT for RUNX2 and TT for VDR. (A and T are the mutant allele genes). Figure1: Facial profile The patient shows a class II profile with slightly retruded man- dible and increased nasal-labial angle. (fig.1) Figure 2: Dental arches