engleski

Detailed characterization of small supernumerary marker chromosomes reveals breakpoint hot spots and narrows down the critical regions of clinical impact.

Array-comparative genomic hybridization (aCGH) was done in 64 small supernumerary marker chromosomes (sSMC). The studied sSMC-specific DNA was derived from glass-needle based microdissection, avoiding by that the problem of mosaicism as present in ~40% of corresponding patients. Furthermore, a detailed analysis of overall 128 characterized breakpoints in non-heterochromatic chromosomal regions of sSMC was done. It turned out that 82.8% and 53.1% of the breakpoints are located within copy number variant regions and regions with segmental duplications, respectively. 6.3% of the breakpoints locate within sequence gaps, making an overall of 90.6% of association of non heterochromatic sSMC-related breakpoints with ‘critical genome structure’. Moreover, approximately three quarters of the breakpoints were concordant with fragile sites. Still, there was a 7.0% overlap of the observed breakpoints and interspersed telomeric sequences (ITS), but only two out of 128 breaks were within an olfactory receptor gene family region. Overall, we present the largest ever done aCGH study in sSMC and provide evidence for hotspots involved in sSMC formation. Deduced from that data it was also possible to characterize regions causing clinical problems if present additionally, for all human chromosomes except for chromosomes 6, 13, X and Y.

Array-comparative genomic hybridization ; aCGH ; small supernumerary marker chromosomes ; sSMC ; microdissection ; breakpoint hot spots

Prema našim saznanjima prvi rad temeljen na array CGH tehnologiji u kojem sudjeluju znanstvenici iz Hrvatske (sa stalnim boravkom u RH).