Backround. The children suffering from a family hypercholesterolaemia (FH) have extremely high risk of development of early atherosclerosis. Aortic pulse wave velocity (aoPWV) is the reliable method of determination of rigidity of vessels allowing to register the earliest changes of a condition of vessels in childhood.
Aim. To study indicators of aortic stiffness among children with FH and healthy children.
Methods. The study included 134 children, of whom 62 were diagnosed FH and 72 healthy children (control group). We analyzed the indicators of 24-hour monitoring of aortic pulse wave velocity (aoPWVVmin, aoPWVVmean, aoPWVmax). Diagnostics of FH was carried out in compliances with criteria of Simon Broome. The studied groups were comparable on age and a gender. The statistical analysis was carried out with use of the IBM SPSS Statistics v.23 program (the developer - IBM Corporation).
Results. Taking into account the peculiarities of physical parameters, age periodization and recommendations for FH therapy in childhood, all children were divided into 3 age subgroups (5-7 years, 8-12 years and 15-17 years). Children with FH and healthy children were comparable by age and sex (p<0.05). 
Analysis of aoPWV showed that no statistically significant differences were found between FH and control in children under 7 years of age (p<0.05). The situation was different in the other two groups. In children with FH at the age of 8-12 years and from 13 to 17 years old, statistically significant high values of aoPWVmin, aoPWVVmean, aoPWVmax were observed compared to their healthy peers (p<0.05). 
Comparison of aoPWV in children with FH by sex revealed that aoPWVmean (5.73±1.34 m/s vs. 4.92±0.91 m/s, p<0.05) and aoPWVmax (7.16±1.73 m/s vs. 5.82±1.26 m/s, p<0.05) were significantly higher among boys than among girls.
The correlation-regressive analysis revealed that in patients with FH, a statistically significant relationship between the age of the child and aoPWVmean (rxy=0.401, p<0.01) and between the age of the child and aoPWVmin (rxy=0.486, p<0.001) was established.  
Conclusions. 1. A reliable increase in aoPWV in FH children compared to their healthy peers was registered from the age of 8 years; 2. aoPWV at FH depends on age of the child; 3.aoPWVmean, aoPWVmax among boys with FH is higher than among girls with FH.

02 - CHANGES IN AORTIC STIFFNESS IN CHILDREN WITH HETEROZYGOUS FAMILIAL HYPERCHOLESTEROLEMIA