[Clinical value of MLPA in the prenatal gene diagnosis of Duchenne muscular dystrophy]

Abstract

Objective: To investigate the clinical value of multiplex ligation-dependent probe amplification (MLPA) in the prenatal gene diagnosis of high risk pregnant women from Duchenne muscular dystrophy (DMD) families.

Methods: The 155 high risk pregnant women from DMD families were recruited from 2005 to 2012 in 4 hospitals in Guangzhou, such as Southern Hospital of Southern Medical University and the Third Affiliated Hospital of Guangzhou Medical University. Among all the samples, 7 were chorionic villus samples taken from early-stage pregnancy and 148 were amniotic fluid samples from mid-stage pregnancy. After the maternal contamination was eliminated, the fetal DMD gene screening was carried out by using MLPA. The mutation rates in DMD exons were calculated in all the 155 families.

Results: (1) Among the 155 fetuses of the DMD high risk pregnant women, there were 72 male fetuses and 83 female fetuses. In the male fetuses, there were 27 sufferers (38%). In the female fetuses, there were 28 carriers (34%). And there were 100 normal fetuses. (2) Among the 27 DMD sufferers, 22 cases were DMD exon homozygous deletions (14.2%, 22/155) and 5 cases were DMD exon duplications (3.2%, 5/155). Among the 28 carriers, 25 cases were gene heterozygous deletions (16.1%, 25/155) and 3 cases were gene heterozygous duplications (1.9%, 3/155). In the 155 families, the DMD mutations mainly occurred in exons 45-52, and the exon 49 had the highest mutation rates of 22 times. (3) Among the 7 cases of prenatal gene diagnosis using chorionic villus samples, 2 fetuses had the identical DMD genotypes with their mothers and probands. One was a DMD sufferer and the other was a carrier. Termination or continuation of pregnancy was suggested based on the genotype of the fetus.

Conclusions: MLPA provides an accurate method in the prenatal diagnosis of DMD. It could be used to distinguish DMD gene homozygous deletions from heterozygous deletions and duplications. Therefore, it is valuable for DMD prenatal diagnosis in high-risk women. Chorionic villus sampling can be applied to the early prenatal diagnosis for DMD disease.