Data from: Cardiac dysfunction in Duchenne muscular dystrophy is less frequent in patients with mutations in the dystrophin Dp116 coding region than in other regions

Background: Duchenne muscular dystrophy (DMD), the most common inherited
muscular disease in childhood, is caused by dystrophin deficiency because
of mutations in the DMD gene. Although DMD is characterized by fatal
progressive muscle wasting, cardiomyopathy is the most important nonmuscle
symptom threatening the life of patients with DMD. The relationship
between cardiac involvement and dystrophin isoforms has not been analyzed.
Methods and Results: The results of 1109 echocardiograms obtained from 181
Japanese DMD patients with confirmed mutations in the DMD gene were
retrospectively analyzed. Patients showed an age-related decline in left
ventricular ejection fraction. Patients were divided by patterns of
dystrophin isoform deficiency into 5 groups. The cardiac dysfunction-free
survival was significantly higher in the group with mutations in the Dp116
coding region than the others, whereas no significant differences in the
other 3 groups. At age 25 years, the cardiac dysfunction-free rate was 0.6
in the Dp116 group, but only 0.1 in others. PCR amplification of Dp116
transcript in human cardiac muscle indicated promoter activation.
Conclusions: Left ventricular ejection fraction in DMD declined stepwise
with age. Cardiac dysfunction was less frequent in Dp116-deficient than
other patients with DMD. Dp116 transcript was identified in human cardiac
muscle for the first time. These results indicate that Dp116 is associated
with cardiac involvement in DMD.