engleski

Cytogenetic and fish studies in patients referred for suspected chromosomal aberrations

Constitutional chromosome aberrations(CCA) cause a large group of genetic disorders and cytogenetic methods are important tool in diagnostics. Although cytogenetic techniques improved rapidly, the frequency of chromosomal aberrations and diagnostic strategy remain important medical problems. We present the results of cytogenetic and FISH studies in 170 children referred to the Department of Medical Genetics for developmental and somatic delay, congenital malformations, dysmorphic features or behavioral problem of unknown etiology (common aneuploidy syndromes were excluded). The aim of this study was to determine the frequency of structural aberrations and evaluate diagnostic algorithm that starts with a clinical examination, followed by cytogenetic and FISH analysis. Cytogenetic analysis was carried out on slides obtained by peripheral blood culture using high resolution GTG-, RBG- and CBG-banding method. FISH studies were performed using WCP-, CEP-, LSI-probes and subtelomere FISH screening assay. Cytogenetic analysis revealed structural chromosome aberrations in 12(7.1%) out of 170 children. FISH analyses with appropriate microdeletion probes were performed in 127 out of remaining 158 patients and microdeletions were identified in 14(11.0%) cases. Rearrangements involving subtelomeric regions were detected in 2(6.5%) out of 31 screened children. In our sample we identified 28(16.5%) children with structural aberrations including 23(13.5%) children with unbalanced rearrangements [dup(16) ; dup(8) ; der(15)t(15 ; 18) ; der(8)t(7 ; 8) ; der(X)t(X ; 6) ; del(2) ; del(14) ; r(9) ; psu idic(X) and 14 interstitial microdeletions], 3(1.8%) with apparently balanced aberrations [inv(13) ; t6 ; 17) ; t(6 ; 10)], and 2(1.2%) with complex apparently balanced abnormalities [t(1 ; 4), t(2 ; 14), inv(3) ; t(6 ; 19), t(2 ; 13)]. This study demonstrates the usefulness of applied diagnostic strategy in the identification of genome imbalances in patients with suspected CCA

Chromosome aberations; frequency; diagnostic algorithm

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