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Epidemiology of progressive muscular dystrophy in Okinawa, Japan. Classification with molecular biological techniques
M Nakagawa1, K Nakahara, H Yoshidome
1Department of Neurology, National Okinawa Hospital, Ginowan, Japan.
Abstract:
We studied the prevalence of various types of progressive muscular dystrophy (PMD) in Okinawa, Japan on December 31, 1989 and the incidence of Duchenne muscular dystrophy (DMD) in 5-year periods from 1957 to 1985. We classified patients with PMD clinically, electrophysiologically, molecular biologically and immunohistochemically with antidystrophin antibody, especially for sporadic cases of DMD, Becker muscular dystrophy (BMD) and limb-girdle muscular dystrophy (LG). The prevalence for all PMD in Okinawa was 7.13 X 10(-5) for DMD, 1.82 X 10(-5) for BMD in the male population, 1.55 X 10(-5) for LG, 1.14 X 10(-5) for congenital muscular dystrophy, 2.03 X 10(-5) for facioscapulohumeral muscular dystrophy (FSH), and 9.13 X 10(-5) for myotonic dystrophy (MD) in the total population. The incidence of DMD in the period 1957-1985 was 15.41 X 10(-5) live-born males (LBM) and 3.21 X 10(-5) LBM for BMD. The incidence has apparently declined in Okinawa since 1975. The prevalence of BMD, FSH and MD was rather high in Okinawa compared with previous reports. Molecular biological techniques for classifying patients were indispensable for the epidemiological study of PMD.
Insights
This study investigated progressive muscular dystrophy (PMD) prevalence in Okinawa, finding higher rates for Becker muscular dystrophy, facioscapulohumeral muscular dystrophy, and myotonic dystrophy. Duchenne muscular dystrophy incidence declined after 1975.
Area of Science:
- Neurology
- Genetics
- Epidemiology
Background:
- Progressive muscular dystrophies (PMD) encompass a group of genetic disorders characterized by progressive muscle weakness and degeneration.
- Understanding the epidemiological landscape of different PMD subtypes is crucial for public health planning and resource allocation.
Purpose of the Study:
- To determine the prevalence of various progressive muscular dystrophies (PMD) in Okinawa, Japan, as of December 31, 1989.
- To ascertain the incidence of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) in 5-year intervals from 1957 to 1985.
- To compare the observed prevalence rates with previous international reports.
Main Methods:
- Clinical, electrophysiological, molecular biological, and immunohistochemical classifications were employed for PMD subtypes.
- Antidystrophin antibody was utilized, with a specific focus on sporadic cases of DMD, BMD, and limb-girdle muscular dystrophy (LG).
- Prevalence data were collected for all PMD types, including DMD, BMD, LG, congenital muscular dystrophy, facioscapulohumeral muscular dystrophy (FSH), and myotonic dystrophy (MD).
Main Results:
- The overall prevalence of PMD in Okinawa was 7.13 X 10(-5) for DMD, 1.82 X 10(-5) for BMD (male population), 1.55 X 10(-5) for LG, 1.14 X 10(-5) for congenital muscular dystrophy, 2.03 X 10(-5) for FSH, and 9.13 X 10(-5) for MD (total population).
- The incidence of DMD was 15.41 X 10(-5) live-born males (LBM) and BMD was 3.21 X 10(-5) LBM during 1957-1985.
- A decline in DMD and BMD incidence was observed in Okinawa after 1975.
- Prevalence rates for BMD, FSH, and MD were notably higher in Okinawa compared to prior studies.
Conclusions:
- Molecular biological techniques are indispensable for accurate epidemiological studies of PMD.
- The study highlights a potentially higher prevalence of certain muscular dystrophies, including BMD, FSH, and MD, in the Okinawan population.
- The observed decline in DMD and BMD incidence warrants further investigation into potential environmental or genetic factors.