Craniofacial geometric morphometrics in the identification of patients with sickle cell anemia and sickle cell trait

OBJECTIVE: The aims of this study were to identify the main characteristics regarding the shape and size of the craniofacial region in patients with sickle cell anemia (SCA) and sickle cell trait (SCT) and in unaffected patients using geometric morphometrics and to check the efficiency of this method. MATERIAL AND METHODS: A cross-sectional analytical study of 45 patients (15 in each group) was performed. Lateral radiographs of the skull were used for the analysis. Seventeen landmarks and semilandmarks were placed for the measurements. The Pocrustes analysis of variance (ANOVA), regression analysis, multivariate analysis of variance, canonical variate analysis, Mahalanobis and Procrustes distances and unweighted pair group method with arithmetic mean (UPGMA) clustering were performed. Allometric effects and sex characteristics were not statistically significant (p > 0.05). RESULTS: There were, however, significant differences (p < 0.05) in craniofacial shape among SCA, SCT and unaffected individuals. Those with SCA showed variations in the shape of the external auditory meatus and at the base of the occipital bone, in addition to the mandibular setback and upper incisor inclination, with a tendency towards prognathism. The individuals with SCT exhibited a similar craniofacial shape to those with SCA, but with slighter variations. Moreover, those with SCT were statistically closer in resemblance to unaffected individuals, given that SCT is not regarded as a disease. CONCLUSION: This demonstrates the efficiency of geometric morphometrics in the categorization of the assessed groups.