The Importance of Classical and Molecular Cytogenetics in the Diagnosis of Microdeletions Microduplications Syndromes

Microdeletions and microduplications syndromes are a well defined group of disorders characterized by loss/ addition of less than 5 Mb of genetic material undetectable by simple karyotype and a particular phenotype. Our study presents the results of investigations of classical and molecular cytogenetic (FISH, Fluorescence in situ Hibridization) in 70 children showing different phenotypic manifestations, such as multiple congenital anomalies, dysmorphic appearance, mental retardation, obesity. After performing classical cytogenetic technique of the 70 cases, in four girls there were diagnosed two visible structural chromosomal abnormalities: DiGeorge syndrome, Distal 18q Deletion syndrome, 15q Duplication syndrome, izocromosome Xq and one boy with 11q24-qter deletion and 38 numerical aberrations were identified: 33 cases of trisomy 21, two cases of monosomy X, two cases of poly Y syndrome and one double aneuploidy, trisomy 21 and poly Y. Using FISH (Fluorescence in situ Hibridization) technique in all the 32 cases, another 5 cases were diagnosed with Prader-Willi syndrome, one with the following: Angelman syndrome, Williams syndrome and 15q Duplication Syndrome, two DiGeorge syndrome, one Jacobsen syndrome, 11q 23-qter deletion and one double aneuploidy. In our study, the efficacy of the classical cytogenetic technique in confirmation of the cases suspected by chromosome abnormality was 61.4% and the FISH technique, was 37,5%.In our study, using both methods of diagnosis, we obtained confirmation of the genetic etiology in only 72.85% of the cases.