Absence of plectin, a large cytoskeleton-associated protein, has been shown to underlie EB-MD. In this study, we report a patient who presented with neonatal blistering and late-onset muscular dystrophy with nail and tooth abnormalities, as well as severe mucocutaneous involvement including laryngeal webs and urethral strictures, features not previously reported. Mutation detection, based on amplification of genomic DNA, followed by heteroduplex analysis and direct nucleotide sequencing, revealed that the proband was a compound heterozygote for two PLEC1 mutations, 4416delC/4359ins13, both resulting in a premature termination codon (PTC) in the plectin rod domain. Since these mutations, and the majority of the previous PTC mutations EB-MD, reside within exon 32, we developed a rapid and sensitive method, the protein truncation test (PTT), to screen for mutations in the two large 3 exons (nos. 32 and 33) of PLEC1 which together comprise ∼75% of the 13.8 kb coding region of the gene. PTT, based on a combination of RT-PCR, transcription and translation, reliably detected mutations in the proband presented in this study, as well as in patients in whom we have previously identified PTC mutations. Thus, PTT provides a rapid and reliable strategy to identify PTC mutations within PLEC1 and potentially in other genes which contain unusually large exons.