A genetic disease that affects males especially characterized by severe muscular degeneration. It is deteriorating disease which usually begins at the age of 4 and progresses rapidly then on. Because of the muscular degeneration there is muscle loss, with muscular loss the person has trouble doing actions like walking or standing and individuals affected with this condition have difficulty walking by the age of twelve.
Genetics
Males are the ones who are usually affected as it is an X linked recessive disease, which means the mutations are found on the x chromosome, since females carry two x chromosomes even if one chromosome is affected, they only become carrier passing this affected gene on to the male offspring and because males only have one x chromosome, they manifest the disease, for a female to become affected they should carry the mutated gene on both the chromosomes
Pathogenesis
The mutated gene is called the dystrophin gene which codes for the protein called dystrophin which is important for the attachment of the cytoskeleton of the muscles to the basal lamina with a lot of other proteins which in turn gives the integrity to the cell.
In this condition because there is an absence of dystrophin the attachment of the cell is not proper leading to permeating of the calcium within the cell. Because there is a disturbance in the ions, some pathways are triggered eventually leading to water entering the mitochondria leading to the destruction of the organelle, this is followed by a cascade of destructive changes which are mediated by reactive oxygen species.
Signs and symptoms
Involves the voluntary muscles mainly the hips, legs and pelvis and then go on to involve the upper limb, symptoms may start manifesting before the age of five. Mainly the motor muscles are affected therefore the child finds it difficult to walk or run. The child has many episodes of falling and overtime losing the ability to walk. One of the main signs is called the Gowers sign, the child who is in a sitting or lying position finds it difficult to stand up. Other abnormalities like scoliosis can also be seen
Treatment
There is no definite treatment and management is focused on symptomatic control. Physiotherapy is very helpful and is performed by Preston physio to improve the motor functions of the patient
Medical treatment includes giving corticosteroids mainly prednisolone and to help with the movement wheel chairs are used.
Diagnosis
Main diagnosis is through genetic testing which can be performed during pregnancy and also the rise creatinine kinase level and the EMG shows muscular weakness. If there is no mutation revealed during DNA testing muscle biopsy can be performed
Prognosis
Prognosis is quite poor for this condition because although the voluntary muscles are affected at first, it may later progress to involve the cardiac and respiratory muscles leading to cardiac and respiratory failure. The average life expectancy of someone with Duchenne muscular dystrophy is around 25- 26 but with proper management this can be extended to 30 years.