Preauricular sinus - transgenerational inheritance

Introduction: The preauricular sinus (PAuS) is a supposedly inherited congenital malformation, which is characterized by a dent, dimple or a foramen on the crus of the auricular helix, although it can also be found on the pinna or on the tragus. The structure is a symptom of some inherited syn­dromes such as Melnick-Fraser and others. Little is known, however, about the exact mechanisms of its transgenerational inheritance, outside of the established genetic syndromes. Materials and Methods: A total of 100 individuals were specifically assessed for the presence of PAuS (51 males, 49 females total; mean age 26.87, standard deviation ±12.53). Individuals identified to have a PAuS were specifically assessed for the presence of the structure amongst relatives. Pedigree charts were made and analyzed to establish the mechanism of transgenerational inheritance. Additional­ly, individuals were also assessed for the presence of other abnormalities, to exclude a broader genet­ic syndrome. Results: Three of the assessed individuals (3%) had a structure complying with the criteria set for PAuS. One of the individuals was, however, adopted and hence no pedigree chart could be made for him. The transgenerational inheritance in the other two subjects, however, depicted the PAuS as a trait inherited in an autosomal dominant fashion, with the first individual showing a classical Men­delian model of inheritance and the second revealing a model of a dominant trait with incomplete penetrance. None of the relatives and individuals complied with criteria for a genetic syndrome with a PAuS. Conclusion: This is the first study of the kind carried out in Bulgaria. Worldwide there has been little to no research on the transgenerational inheritance of PAuS after the 1950s. Our results support the findings of those studies. The pattern of inheritance is autosomal dominant with reduced penetrance.