Duchenne muscular dystrophy is a progressive muscle disorder that causes loss of muscle function and independence. Duchenne is the most common fatal genetic disorder diagnosed during early childhood, affecting approximately one out of every 3,500 males. There are approximately 15,000 young men living with Duchenne in the United States today. The gene mutation that causes Duchenne can happen during any pregnancy, even if no one else in the family is affected. To date, there is no cure or treatment that can completely stop the progression of Duchenne muscular dystrophy. Young men with Duchenne typically live into early adulthood.
Duchenne Muscular Dystrophy (DMD) is an x-linked recessive disease. Mothers are the carriers. That means it can be found in boys that are related by female relatives – brothers, uncles, cousins. But because it is recessive not all boys that are related will have the genetic code for DMD. Sometimes it skips a child or a generation.
Sometime it’s a completely random mutation.
This is the case of Mr. Sensitive. He has a genetic mutation that causes a deletion on his dystrophin gene. This is the DNA sequence responsible for the way muscle protein is made. Dystrophin is a protein used in muscle structure. Changes in the dystrophin gene result in changes in the way muscles are built and re-built over time.
Everyone’s muscles break down over time. Everyone’s muscle cells die, only to be replaced by new cells. That is what the dystrophin gene does. It helps re-build muscles. Mr. Sensitive’s muscle cells will not be re-built. They will be replaced by fat cells.
What does this mean?
Eventually his muscles will stop working.
He will be unable to walk, unable to eat without assistance, unable to use the washroom without assistance, and eventually unable to breathe without assistance.
We are lucky. We are in the ‘good’ part of Duchenne MD right now.
Duchenne MD has a misleading trajectory. The child shows initial gross and fine motor delays, and slowly progresses. Physical ability peaks at around ages 6-8 years, then gradually declines as muscle cells are replaced with fat cells. The child is in a wheelchair fulltime by age 12. Only in very recent years has life expectancy exceeded late teens.
People who have Duchenne MD can now hope to live to age 30, with significant medical care and good luck. Medical interventions such as steroids (to preserve muscle function for as long as possible), ventilators, steel rods in the spine to correct scoliosis, and g-tubes for feeding help the individual live for as long as possible.
Mr. Sensitive is currently on steroids to help preserve his muscle mass. We’re taking baby steps toward a cure.