Becker Muscle Dystrophy - a variant of DMD

Introduction

Muscular dystrophies are genetic disorders. They are characterized by muscle wasting and weaken, which is progressive. Microscopic changes result in the weakening and wastage of the muscles. Muscle degeneration occurs over time, declining muscle strength. Becker muscular dystrophy is a variant muscle dystrophy of Duchenne muscular dystrophy (DMD). It is named after a German doctor Peter Emil Becker.

Becker muscular dystrophy is a milder version of Duchene muscle disorder, which is inheritable. It occurs mostly in teens and young adults. Its course is slower and less predictable compared to Duchene muscle dystrophy. Skeletal and cardiac muscles are vulnerable to this disorder. The Becker muscle disorder exclusively affects males and, in rare cases, females.

Causes of Becker Muscle Dystrophy

A mutation of the dystrophin gene causes Becker muscular dystrophy. The mutation of the dystrophin gene causes a deficiency of protein dystrophin, which is an essential building block for muscles, giving the muscles structure and strength. Lack of dystrophin cause muscles to weaken and die with time.

Inheritance of Becker Muscular Dystrophy

Becker muscular dystrophy is an X-linked recessive genetic defect. It is inherited through a defective X-chromosome. Females have two X-chromosome, one from the mother and the other from the father. On the other hand, males have only one X-chromosome, from the mother and one Y-chromosome, from the father. Since females have two X-chromosomes, they have a lower risk of getting Becker muscular dystrophy. In case one X-chromosome has the defective gene, the other contains a copy of the gene that compensates for the other. Females rarely get the disorder in case of a defective X-chromosome but can transmit the defective gene to their male children. The disorder may cause heart problems in females, including dilated cardiomyopathy.

Males having only one X-chromosome have a high risk of getting the disorder. In case of inheriting a defective X-chromosome, and lacking a second chromosome to compensate for the defective gene, they will develop the signs of Becker muscular dystrophy. In other cases, the mutation is not inherited but may develop spontaneously within the early stages of embryo development. The risk of passing the Becker muscular dystrophy gene to offspring by a mother is 50% to every child she bears. The male children will develop Becker muscular dystrophy symptoms with time during the early stages. Females become carriers of the Becker muscular dystrophy gene.

Symptoms of Becker Muscular Dystrophy

The symptoms begin during childhood stages or early adulthood. They progress with time and slowly get worse. Affected people have difficulty walking and muscle skills such as jumping, falling, and muscle mass loss. The symptoms move on to affect the heart muscles, causing dilated cardiomyopathy. The heart condition weakens it, interfering with efficient blood pumping. Cognitive problems, fatigue, and breathing problems are other symptoms of Becker muscular dystrophy.

Diagnosis of Becker Muscular Dystrophy

Becker muscular dystrophy has similar symptoms with several diseases. Such diseases include Becker muscular dystrophy, limb-girdle muscular dystrophy, and spinal muscular atrophy. It is, therefore, essential to get the proper diagnosis. A blood test is carried to examine levels of enzyme creatine kinase. High levels of the enzyme indicate muscle problems that cause the enzyme leak. A genetic test is also carried out to determine the type of genetic mutation. The test analyzes the dystrophin gene to confirm the diagnosis. Muscle biopsy is also carried to determine the problem with the muscles and can show reduced dystrophin expression.

Conclusion

There is no specific cure for any muscular dystrophies. A variety of available treatments help with relieving the symptoms. These treatments include physiotherapy, the use of supportive devices, speech therapy, and surgery in some cases. Physiotherapy helps in teaching techniques to conserve energy, while supportive tools help keep muscles flexible. Finally, surgery helps relieve advanced tendon problems.