Duchenne muscular dystrophy.
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Biomedical subjects
Publications and source records attributed to W Douglas Biggar.
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OBJECTIVE: To examine alendronates side-effect profile and effect on bone mineral density (BMD) in deflazacort-treated boys with Duchennes muscular dystrophy (DMD) and low BMD. DESIGN: Before-after trial. SETTING: Neuromuscular clinic at a children's hospital in Canada between 1999 and 2000. PARTICIPANTS: All consenting boys with DMD who had z scores less than -1.00 (spine and/or total body) and in whom BMD testing was feasible. INTERVENTION: Boys received .08 mg.kg(-1) .d(-1) of alendronate orally, with 750 mg of daily calcium and 1000 IU of vitamin D. BMD, height, weight, physical activity, Tanner stage, and adverse effects were followed for 2 years. MAIN OUTCOME MEASURES: BMD z scores at the lumbar spine (L1-4) and total body. RESULTS: Of the 42 eligible boys assessed, 23 had low BMD; for 16 of the 23, future BMD testing was feasible. Mean age was 10.8 years (range, 6.9-15.6 y). Mean baseline z scores at the total body and spine were -0.80 and -1.94, respectively. At 2 years, mean z scores were unchanged. Furthermore, alendronate response varied by baseline age. In multivariable analysis, improvement in total body and spine z scores was associated with younger age at baseline ( P =.01 for both). CONCLUSIONS: In deflazacort-treated boys, alendronate had a positive effect on BMD z scores; the effect was greatest when given early in the course of disease.
BACKGROUND: Scoliosis due to progressive muscle weakness occurs in almost all males with Duchenne muscular dystrophy, and it progresses relentlessly. Previous studies have shown that corticosteroid treatment slows the decline in muscle strength and stabilizes muscle strength in patients with this disease. We hypothesized that steroids may also attenuate the development of scoliosis. The purpose of this study was to compare the prevalence of scoliosis in male patients with Duchenne muscular dystrophy who received steroids with a control group of such patients who did not. METHODS: A group of seven to ten-year-old boys with Duchenne muscular dystrophy who were able to walk were enrolled in a nonrandomized comparative study to determine the effect of deflazacort (a derivative of prednisone) on muscle strength and pulmonary function. Thirty patients were treated with deflazacort (treatment group), and twenty-four were not (control group). The patients were matched for age and pulmonary function at baseline. To assess the development of scoliosis, the patients in each group were followed for at least five years. Survival curves were plotted to determine the chance of scoliosis of >/==" BORDER="0">20 degrees developing. The difference between the groups with respect to the chance of scoliosis developing was determined with Kaplan-Meier analysis. RESULTS: A curve of >/==" BORDER="0">20 degrees developed during the follow-up period in sixteen (67%) of the twenty-four patients in the control group but in only five (17%) of the thirty patients in the treatment group. Fifteen of the twenty-four patients in the control group underwent spine surgery, at a mean age of thirteen years, whereas only five of the thirty patients in the treatment group underwent spine surgery, at a mean age of fifteen years. Kaplan-Meier analysis demonstrated a significant difference between the two groups with regard to development of scoliosis of >/==" BORDER="0">20 degrees (p < 0.001). Cataracts developed in ten patients in the treatment group, and stress fractures developed in three patients in the treatment group. Patients in the treatment group weighed a mean of 3.7 kg more than did those in the control group. CONCLUSIONS: Steroid treatment slows the progression of scoliosis in males with Duchenne muscular dystrophy; however, longer-term evaluation will be necessary to determine if the treatment prevents the development of scoliosis or just delays its onset. At the very least, steroid treatment delays the need for spinal surgery. LEVEL OF EVIDENCE: Therapeutic study, Level II-1 (prospective cohort study). See Instructions to Authors for a complete description of levels of evidence.
The cloning of the dystrophin gene has led to major advances in the understanding of the molecular genetic basis of Duchenne, Becker, and other muscular dystrophies associated with mutations in genes encoding members of the dystrophin-associated glycoprotein complex. The recent introduction of pharmaceutical agents such as prednisone has shown great promise in delaying the progression of Duchenne muscular dystrophy but there remains a need to develop more long-term therapeutic interventions. Knowledge of the nature of the dystrophin gene and the glycoprotein complex has led many researchers to think that somatic gene replacement represents the most promising approach to treatment. The potential use of this strategy has been shown in the mdx mouse model of Duchenne muscular dystrophy, where germ line gene transfer of either a full-length or a smaller Becker-type dystrophin minigene prevents necrosis and restores normal muscle function.