[Multifactorial nature of Chiari type I malformation].

The aim of the study was to analyze genetic aspects of Chiari type I malformation (CMI) using clinical neurological examination and magnetic resonance imaging data on the craniovertebral region in 13,500 outpatients, 364 inpatients with CMI and 91 first-degree relatives of 47 probands with CMI. Higher CMI frequency (3.9%) in the outpatients with neurological signs, and CMI clinical and morphologic polymorphism have been discovered, the women being mostly affected and the men displaying more severe clinical picture of the disease. In the group of patients with the most severe CMI form, higher parent's endogamy marriage frequency was observed. The CMI clinical and morphologic features in the probands and their relatives were identical and the frequency of the CMI presence in the first-degree relatives depended on the proband's pathology severity. The results obtained support the evidence for CMI multifactorial nature.