Development of a comprehensive real-time PCR assay for dystrophin gene analysis and prenatal diagnosis of Chinese families.

BACKGROUND: To develop a comprehensive method to analyze deletions or duplications of the dystrophin gene in both patients and carriers of Duchenne muscular dystrophy (DMD), likewise applied to prenatal diagnosis.

METHODS: A total of thirty Chinese families were recruited, composed of 29 DMD affected males and 38 female relatives containing four pregnant women. Deletions were previously screened by multiplex PCR. A comprehensive real-time PCR assay using SYBR Green I dye was performed for the initial detection of duplications in patients with a seven-exon primer set, carrier detection for female relatives and prenatal diagnosis for the 4 of them. The results were later confirmed by multiple ligation-dependent probe amplification (MLPA) and linkage analysis.

RESULTS: Three out of 4 duplications were first discovered by real-time PCR. Carrier status was ascertained in 22 and rejected in the remaining sixteen female relatives. Furthermore, 4 fetuses were diagnosed as two normal females, one normal male and one female carrier, respectively.

CONCLUSIONS: Our real-time PCR assay is useful in duplication screen with a detection rate of >70%, as well as rapid and reliable in both carrier detection and prenatal diagnosis of DMD families with known deletions and duplications.