A protein truncation test for Emery-Dreifuss muscular dystrophy (EMD): detection of N-terminal truncating mutations

X-linked Emery-Dreifuss muscular dystrophy (EMD) is caused by mutations in the emerin gene. Since the emerin gene is ubiquitously expressed and since all EMD mutations published so far should be detectable by an RNA-based mut ation assay, we have designed a protein truncation test for emerin. To faci litate the detection of mutations in the translation initiation site, repor ted for several EMD-cases, the standard tailed forward PTT-primer had to be modified. The effectiveness of the assay was established by a mutation sca n in four EMD-patients. Two patients could be shown to carry emerin mutatio ns, one affecting the ATG translation initiation codon. The PTT-assay did n ot detect a mutation in the two other patients. Since an immunohistochemica l analysis of patient-derived cells revealed normal emerin levels, these pa tients are thus affected by another muscular dystrophy, most likely autosom al dominant EMD. (C) 1999 Elsevier Science B.V. All rights reserved.