| Objective:Mental retardation is a common neurodevelopmental disease,the population incidence is about 3%. Chromosome subtelomeric area micro-structural abnormalities are important cause resulting in mental retardation, but they can't be detected by conventional cytogenetic method.In this study, patients with idiopathic mental retardation were analyzed by multiplex ligation-dependent probe amplification (MLPA).Methods:The patients who have normal or abnormal karyotype were objectives,the Netherlands MRC-Holland's P070 MLPA subtelomeric probe kit was choosed, genomic DNA of patients were extracted, after denaturation, hybridization, ligation, amplification and so on. The products were separated by ABI company 3700 capillary electrophoresis sequencing instrument.A credible MLPA technology platform was established.118 patients with mental retardation,whose karyotyping analysis found no abnormalities were objectives,were detected by MLPA.Patients suspected of chromosomal abnormalities would be verified by FISH technology.Results:A mature and stable MLPA technology was developed through optimized the quality of DNA,adjust the dosage of DNA,the time of denaturation,the condition of PCR the time and voltage of capillary electrophoresis. Applicating MLPA in detecting patients with mental retardation, chromosomal subtelomeric areas abnormalities were found in 6 cases,respectively,lp36.3 terminal deletion, 1p terminal duplication,15q terminal deletion,15q terminal duplication,22q terminal deletion,and one case of 12q terminal deletion combined 17p terminal duplication. Verificafion of FISH technology, the results are consistent.Conclusion:MLPA technology provides a new diagnostic technique for etiologic detection of mental retardation, and a proof for genetic counseling and prenvention on recurrent risk.Discovery of this 6 abnormal patient,provide new material for studying relationship between phenotype and genotype,and searching for disease gene in mental retardation.
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