OBJECTIVETo establish a strategy for screening and diagnosing common microdeletion and microduplication syndromes among children with idiopathic mental retardation and development abnormalities.

METHODSPotential chromosomal variations among patients with unexplained mental retardation, cardiac anomalies, particular facial features, learning disabilities and other clinical characteristics were detected with bacterial artificial chromosome BACs-on-Beads (BoBs) technique and karyotyping. Positive results were verified with array-based comparative genomic hybridization (Array-CGH).

RESULTSFifty eight of the 60 patients had a normal chromosome karyotype. Ten patients with microdeletion and microduplication syndromes were detected by BoBs, which included two positive cases identified through chromosome karyotyping. Two patients were respectively diagnosed as Smith-Magenis syndrome and Prader-Willi/Angelman syndrome by BoBs and the results were confirmed by Array-CGH.

CONCLUSIONBoBs is capable of detecting chromosome microdeletion and microduplication with high specificity and throughput, which can compensate the shortcomings of conventional cytogenetic technology and will be widely applied for clinical diagnosis.