Duchenne muscular dystrophy (DMD) is a progressive muscle disease. No curative therapy is currently available, but in recent decades standards of care have improved. These improvements include the use of corticosteroids and mechanical ventilation.To present a detailed population based report of the DMD disease course in The Netherlands (1980-2006) and evaluate the effect of changes in care by comparing it with an historical Dutch DMD cohort (1961-1974).Information about DMD patients was gathered through the Dutch Dystrophinopathy Database using a standardized questionnaire and information from treating physicians.The study population involved 336 DMD patients (70% of the estimated prevalence), of whom 285 were still alive. Mean age at disease milestones was: diagnosis 4.3 years, wheelchair dependence 9.7 years, scoliosis surgery 14 years, cardiomyopathy (fractional shortening <27%) 15 years, mechanical ventilation 17 years and death 19 years. Within our cohort, corticosteroid use was associated with an increased age of wheelchair dependence from 9.8 to 11.6 years (p < 0.001). When comparing the recent cohort to the historical cohort, mean survival improved from 17 to 27 years (p < 0.001).The current study gives detailed information about the disease course of DMD patients, provides evidence for the positive effect of steroid treatment and mechanical ventilation and supports the use of patient registries as a valuable resource for evaluating improvements in care.
The locus DXS269 (P20) defines a deletion hotspot in the distal part of the Duchenne Muscular Dystrophy gene. We have cloned over 90 kilobase-pairs of genomic DNA from this region in overlapping cosmids. The use of whole cosmids as probes in a competitive DNA hybridization analysis proves a fast and convenient method for identifying rearrangements in this region. A rapid survey of P2O-deletion patients is carried out to elucidate the nature of the propensity to deletions in this region. Using this technique, deletion breakpoints are pinpointed to individual restriction fragments in patient DNAs without the need for tedious isolation of single copy sequences. Simultaneously,the deletion data yield a consistent restriction map of the region and permit detection of several RFLPs A 176 bp exon was identified within the cloned DNA, located 3’ of an intron exceeding 150 Kb in length. Its deletion causes a frameshift in the dystrophin reading frame and produces the DMD phenotype. This exon is one of the most frequently deleted exons in BMD≤DMD patients and its sequence is applied in a pilot study for diagnostic deletion screening using Polymerase Chain Reaction amplification
Duchenne and Becker muscular dystrophy are caused by a mutation in the dystrophin gene, located on the short arm of the X chromosome. Three so called dystrophinopathy patients, a women aged 54 and two men aged 23 and 21 years, suffered from a severe dilated cardiomyopathy. Such a cardiomyopathy can develop in both carriers and patients. In addition, it is often more important for prognosis than muscle weakness. For these two reasons it is important to screen both groups for (early) cardiological abnormalities. If these are present, regular follow-up is necessary to start timely therapy. When cardiological investigations yield normal results, it is advised to screen carriers with a five-year interval. Dystrophinopathy patients should be checked every year, because the cardiomyopathy sometimes develops and deteriorates over a short period of time. Patients with dilated cardiomyopathy and with a positive family history for dilated cardiomyopathy, muscle weakness or high serum creatine kinase activity should be screened for a mutation in the dystrophin gene.
