Duchenne muscular dystrophy prevalence

Deficiency of dystrophin is the main canse of mnscnlar dystrophy mutation in the gene causes Duchenne muscular dystrophy, a severe recessive X-linked form of muscular dystrophy characterised by rapid progression of muscle degeneration, which eventually leads to loss of ambulation and death. This affliction affects 1 in 3500 males, making it the most prevalent of muscular dystrophies. In general, only males are afflicted, though females can be carriers. 

Although the incidence of SDB has not been systematically examined in neuromuscular disorders (NMD), many case series have been published in different diseases (58-62). According to Labanowski et al. (58), significant SDB with a respiratory disturbance index >15/hr, occurs in up to 42% of patients with NMD, from 16.7% in early stages of ALS (59) to 57% in Duchenne muscular dystrophy (DMD) (60). The severity, duration, and distribution of muscle weakness in NMDs influence the prevalence of SDB. Ragette et al. (63) noted progression of SDB from rapid eye movement (REM) elated hypopneas to REM-related mixed hypopneas and hypoventilation, followed by both REM and non-REM hypoventilation through to diurnal respiratory failure. 

Jeppesen J, Green A, Steffensen BF, et al. The Duchenne muscular dystrophy population in Denmark, 1977-2001 prevalence, incidence and survival in relation to the introduction of ventilator use. Neuromuscul Disord 2003 13 804-812. 

The major benefit of NPPV is the improvement in survival, although this has only been demonstrated in patients with NMD (16). In Denmark, the benefit of NPPV on survival of patients with Duchenne muscular dystrophy was evaluated between 1977 and 2001 (17). While overall incidence remained stable at 2 per 10 persons, prevalence rose from 3.1 to 5.5 per 10, mortality fell firom 4.7 to 2.6 per 100 years at risk, and the prevalence of ventilator users rose from 0.9 to 43.4 per 100. Ventilator use is probably the main reason for this dramatic increase in survival. An increase in survival has not been demonstrated in CF patients. 

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