The following report from the MHC-database is based on the latest version of the Mun-H-Center Observation Chart that has been in use since 2008. Please note, that this report exclude children younger than 3 years.
Reports based on the original forms (1996-2008) are presented at the bottom of this page - below the description of the diagnosis
Estimated occurrence
The total number of persons in Sweden with Becker muscular dystrophy is unknown; however , its incidence is estimated to be about 40 per 1 000 000 male inhabitants. The disease occurs near ly exclusively in boys.
Etiology
The disease is caused by a mutation in the dystrophin gene. The type of mutations occur ring in Becker muscular dystrophy results in severe deficiencies of the protein dystrophin in the muscle fibers. Dystrophin is important for muscle fiber cohesion. The absence of dystrophin renders the muscle fibers more susceptible to degeneratation. The dystrophy gene is located on the X chromosome. In about a third of the cases, the disease is caused by a new mutation.
General symptoms
The symptoms associated with Becker muscular dystrophy closely resemble those of Duchenne muscular dystrophy but are milder. Pronounced symptoms may however sometimes occur. Although muscle weakness is observed in a few cases during infancy, symptoms appear much later in many. Muscle weakness nearly always begins in the legs. About 20% of the cases will require some aid of a wheelchair; the age at which this occurs greatly varies. Muscle weakness also often progresses with age to the upper body and arms. As dystrophin is normally found in the skeletal musculature and heart muscle, as well as to a lesser degree in the central nervous system, symptoms from the heart and central nervous system may occur. Most have no symptoms from the respiratory tract.
Orofacial/odontological symptoms
Muscle weakness in the masticatory and facial muscles, especially if occurring at an early age, may lead to malocclusions. Muscle strength and endurance in the masticatory musculature may gradually decrease. It then becomes more difficult to masticate food, which in turn may eventually lead to altered dietary habits. In cases of reduced muscle strength in the arms and hands, toothbrushing may be difficult.
Orofacial/odontological treatment
- Problems in managing toothbrushing and dental care due to tired and weak arm and jaw muscles justify extra prophylactic dental care.
- An or thodontist should be consulted between the ages of 7 and 9 in order to identify dental aberrations or malocclusions and to plan any necessary orthodontic treatment.
- Orofacial assistive devices should be tried when needed; among these, an electric toothbrush may be of great help.
- Eating difficulties should be investigated and treated by a specialist team.
Sources
The rare disease database of the Swedish National Board of Health and Welfare.
The MHC database - The Mun-H-Center database of orofacial manifestations in rare diseases.
