[Incidental discovery of DMD gene deletions by chromosomal microarray analysis]

Area of Science:

• Medical Genetics
• Prenatal Diagnosis
• Molecular Biology

Background:

• Duchenne/Becker muscular dystrophy (DMD/BMD) is a significant genetic disorder.
• Prenatal diagnosis typically relies on family history and karyotyping.
• Ultrasonographic soft markers can indicate potential fetal abnormalities.

Purpose of the Study:

• To evaluate the utility of chromosomal microarray analysis (CMA) for detecting Duchenne muscular dystrophy (DMD) gene deletions during prenatal diagnosis.
• To assess CMA's effectiveness in cases lacking a family history of DMD/BMD.

Main Methods:

• G-banded karyotyping and CMA were performed on fetal samples.
• Denaturing high-performance liquid chromatography (DHPLC) was used for mutation detection in maternal blood.
• Ultrasonographic soft markers guided sample selection in the absence of family history.

Main Results:

• CMA identified DMD gene deletions in two fetuses with normal karyotypes and no family history.
• Fetus 1 had a deletion encompassing DMD exons 10-16, confirmed in the mother.
• Fetus 2 had a deletion encompassing DMD exons 41-44, not detected in the mother.

Conclusions:

• CMA significantly improves the detection rate of DMD gene deletions in prenatal settings.
• This technique is valuable for identifying single-gene deletion disorders, even without prior family history.
• Prenatal diagnosis can be enhanced by incorporating CMA for specific genetic conditions.