Early-progressive dilated cardiomyopathy in a family with Becker muscular dystrophy related to a novel frameshift mutation in the dystrophin gene exon 27

We report a family in which two male siblings with becker muscular dystrophy (bmd) developed severe dilated cardiomyopathy (dcm) and progressive heart failure (hf) at age 11 years; one died at age 14 years while awaiting heart transplant and the other underwent left ventricular assist device implantation at the same age. genetic analysis of one sibling showed a novel frameshift mutation in exon 27 of duchenne muscular dystrophy (dmd) gene (c.3779_3785delctttggainsgg), in which seven base pairs are deleted and two are inserted. although this predicts an amino-acid substitution and premature termination (p.thr1260argfs*8), muscle biopsy dystrophin immunostaining instead indicates that the mutation is more likely to alter splicing. despite relatively preserved skeletal muscular performance, both the siblings developed progressive hf secondary to early-onset dcm. in addition, their 7-year-old nephew with delayed gross motor development, mild proximal muscle weakness and markedly elevated serum creatine kinase level (>13 000 iu l−1) at 16 months was recently demonstrated to have the familial dmd mutation. here, we report a novel genotype of bmd with early-onset dcm and progressive lethal hf during early adolescence.