Application of MLPA technology in molecular diagnosis of three inherited diseases

Abstract

Objective To evaluate multiplex ligation-dependent probe amplification (MLPA) as a senetic diagnostic method to detect copy number variants (CNVs) in SMA,DiGeorge syndrome and CAH. Methods Genomic DNA was extracted from peripheral blood of 21 patients and their family members received in Shanghai Children′s Medical Centre during February 2010 to February 2011.The procedure of MLPA includes hybridization of probe and target sequence,ligation,PCR amplification,capillary electrophoresis and data collection.MPLA data was analyzed by GeneMarker® software.The MLPA results were compared with conventional PCR-enzyme method and chromosomal microarray analysis. Results All of the 3 probands in SMA pedigrees suffer homozygous loss of exon 7 and 8 of SMN1 gene (copy number state was zero),and their parents have heterozygous loss on exon 7 and exon 8,respectively.Heterozygous deletions encompassing TBX1 were detected in 3 DiGeorge syndrome patients (copy number state≈0.5).The result of MLPA was confirmed by genomic microarray analysis,and the variant was scaled as a 1.3 Mb deletion.Various deletions including pathogenetic gene CYP21A2,the pseudogene CYP21A1P and module gene C4B were detected in six of eight CAH patients. Conclusions As a complement and enhancement of conventional methods for detecting CNVs. MLPA is effective in relative quantitative detection of copy number variations of pathogenic gene in SMA,DiGeorge syndrome and CAH patients and carriers.(Chin J Lab Med,2013,36:136-141) Key words: Nucleic acid amplifecation techniques; Muscularatrophy; spinal; DiGeorge syndrome; Adrenal hyperplasia; congenital