Methylation-specific multiplex ligation-dependent probe amplification in diagnosis of Prader-Willi syndrome and Angelman syndrome

Objective: To verify the sensitivity and reliability of methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and to develop a simple, accurate, reliability method of genetic diagnosis for AS and PWS.

Methods: Peripheral blood samples were collected from 4 suspected AS patients, 2 suspected PWS patients, 2 normal persons, and 2 molecular biologically proven positive controls (1 AS patient and 1 PWS patient). DNA was extracted and purified. MS-MLPA was used to detect the methylation of the CpG dinucleotide and the copy number in the 15q-q13 region. The results of MS-MLPA were confirmed by MSP.

Results: Three cases with maternal deletion on 15q11-q13 region and one case with paternal uniparental disomy (UPD) or imprinting center defect in 15q11-q13 region were found in the 4 suspected AS patients. One PWS case was found to be with paternal deletion in 15q11-q13 region and the other with paternal deletion in 15q11-q13 region or UPD or imprinting center defect in 15q11-q13 region.

Conclusions: MS-MLPA is a simple, rapid, accurate, and reliable method of genetic test.