A cDNA clone from the Duchenne/Becker muscular dystrophy gene

Area of Science:

• Genetics
• Molecular Biology
• Human Disease Research

Background:

• Duchenne muscular dystrophy (DMD) is a common X-linked disorder affecting 1 in 3,000 male births.
• Both DMD and Becker muscular dystrophy (BMD) are X-linked, with affected females often having X-autosome translocations at band Xp21.
• Previous studies localized the DMD/BMD gene to chromosome band Xp21.

Purpose of the Study:

• To isolate and characterize DNA clones from the Xp21 region associated with DMD/BMD.
• To identify DNA fragments that can detect deletions in patients with DMD.
• To isolate cDNA clones that detect transcripts from the DMD/BMD gene.

Main Methods:

• Cloning DNA fragments from patients with Xp21 deletions and X-autosome translocations.
• Using subclones to detect deletions in DMD patients.
• Isolating fetal and adult muscle complementary DNA (cDNA) clones corresponding to specific loci.

Main Results:

• DNA clones (pERT 87 and XJ) representing the DXS164 and DXS206 loci were isolated.
• Subclones detected deletions in approximately 11% of DMD patients.
• A 16-kilobase (kb) transcript was detected using fetal muscle cDNA from DXS164 and adult muscle cDNA from DXS206, with the latter clone spanning multiple loci and a large intron.

Conclusions:

• The cloned DNA fragments are valuable tools for detecting deletions in DMD patients.
• The identified cDNA clones correspond to the DMD/BMD gene transcript.
• The translocation in one patient occurred within a large intron, disrupting the DMD/BMD gene and causing the disease.