EXON-44 NONSENSE MUTATION IN 2 DUCHENNE-MUSCULAR-DYSTROPHY BROTHERS DETECTED BY HETERODUPLEX ANALYSIS

Utilizing a heteroduplex method, we screened the dystrophin exon 43-45 region for point mutations, including small deletions and insertions. The method depends upon the formation of a heteroduplex between wild- type and mutant DNA PCR products. DNA specimens from one hundred and f our DMD patients without detected deletions or duplications were multi plexed amplified for exons 43, 44, and 45. The PCR products were mixed with the PCR products from nonaffected controls, electrophoresed, and examined for the presence of altered mobility heteroduplex bands. An exon 44 nonsense mutation in two DMD brothers and a common intron 44 p olymorphism were identified using this approach. Although the exon 44- 45 region is a hotspot for deletion breakpoints, it does not appear to be prone to point mutations. The technique is extremely useful for sc reening several exons simultaneously and it allowed us to screen a lar ge number of patients. (C) 1993 Wiley-Liss, Inc.