title: The association between blood groups and maxillofacial deformities.
abstract: BACKGROUND
  Blood group is a genetic characteristic which is associated with some diseases and deformities. Multifactorial characteristics of facial development make it difficult to predict a genetic pattern in a specific maxillofacial deformity, but epidemiological evaluations can reveal relationships between such deformities and some genetic characteristics or accompanied diseases, and this will help to recognise and treat them. The aim of this study is evaluation of the relationship between blood groups and maxillofacial deformities.
  
  
  METHODS
  In this study, blood groups of 190 patients with maxillofacial deformities who had had orthognathic surgery in Alzahra hospital, Isfahan, were compared with the general Iranian population.
  
  
  RESULTS
  Among 190 patients, 93 cases (49%) were men and 97 cases (51%) were women. Fifteen cases (8%) were < 20 years old, 130 cases (68%) were 20-30 years old, and the others (45 cases, 24%) were > 30 years old. The blood group distribution in our samples was as follows: blood group O = 76 cases (40%), blood group A = 58 cases (30%), blood group B = 41 cases (22%), and blood group AB = 15 cases (8%). Among these patients, 31 cases (16%) had maxillary deformities and 27 cases (14%) suffered from mandibular deformities while the other 132 cases (70%) had bimaxillary problems. The Chi-square test showed statistically significant differences between the blood group distribution of the patients of this study and the normal Iranian population (P < 0.001).
  
  
  CONCLUSIONS
  It was shown that among different blood groups; those with blood group B have a greater likelihood of association with maxillofacial deformities. On the other hand, the probability of the association of such deformities was the least with blood group A.
authors.forename: Rasoul
authors.initials: R
authors.lastname: Gheisari
authors.forename: Mehdi
authors.initials: M
authors.lastname: Ghoreishian
authors.forename: Bijan
authors.initials: B
authors.lastname: Movahedian
authors.forename: Amrolah
authors.initials: A
authors.lastname: Roozbehi