Variants of the centromeric region of the chromosome 9 belong to the most common human karyotype abnormalities (1-4% in general population). Most frequent among the variants are the shortening (qh-) or the enlargement (qh+) of the heterochromatin area, the pericentric inversion inv(9)(p12q13) is also quite common; the other variants are more rare.
In our analysis we used FISH method based on specific combination of centromeric and BAC-probes. The used method was effective in visualization of inversions, duplications and deletions in tracked area.