Duchenne muscular dystrophy is one of nine major muscular dystrophy and is a genetic disorder that occurs due to decreased levels of the protein complex dystrophin (“Understanding Muscular Dystrophy”, 2017). The lack of this particular protein causes the rapid weakening and degeneration of muscles throughout the body, which can lead to severe consequences for the patients affected. Early stages of Duchenne muscular dystrophy affects the shoulder muscles, upper arm muscles, and the muscles of the hip and thigh.
Later stages of DMD extends throughout the arm and leg muscles and will eventually become life threatening when heart and respiratory muscles degrade or become severely weakened (“Duchenne Muscular Dystrophy (DMD)”, 2018).The symptoms of this disorder are typically found in young boys between ages 3-5 years old (“Duchenne Muscular Dystrophy (DMD)”, 2018). Since the disorder has an X-linked recessive mode of inheritance, it is extremely uncommon for females to inherit the disorder in comparison to males. In fact, sons of women who carry the gene have a 50% chance of having the disorder; conversely, daughters of women who are carriers of the gene only have a 50% chance of being carriers of the disorder.This helps illustrate the significant difference in the occurrence of the disorder in males in comparison to females.
The disorder itself is fairly uncommon amongst the general population in which there is a 1/3600 chance of the disorder occurring in male infants (Duchenne muscular dystrophy, 2016).DMD is caused by mutations in the dystrophin gene which codes for the protein complex dystrophin. When dystrophin production ceases in the body, the structural link between the muscle cytoskeleton and extracellular matrix does not occur and therefore the muscles in the body cannot maintain its proper form (DMD gene – Genetics Home Reference, 2017). Essentially, without Dystrophin, the body is unable to produce a structural link between the muscle exoskeleton and the extracellular matrix, meaning that the muscle fibres in the body cannot be strengthened or protected when the muscle contracts and expands.
This leads to the gradual muscle degradation as the muscle fibres in the body continuously contract and relax without the proper protection that Dystrophin would typically provide. In patients with DMD, the dystrophin gene is partially deleted or mutated. This prevents the functional dystrophin from being produced, leading to degradation and death of cells in the skeletal and cardiac muscles as the muscles are being repeatedly used.This in turn results in the characteristic muscle weakness and heart problems seen in patients with the disorder(DMD gene – Genetics Home Reference, 2017).This muscle weakness is typically found in the patients’ infancy and can lead to symptoms of problematic motor skills, intellectual disabilities and congestive heart failure or cardiomyopathy (abnormal heart muscle).
Patients with this disorder lose their ability to walk by the age of 12 and will likely be limited to the use of a wheelchair. By their teens, severe breathing problems and heart diseases arise, and death normally occurs in their late teens or early 20’s (“Duchenne muscular dystrophy”, 2016).