Duchenne affects approximately 1 in every 3,500 boys that are born but only around 1 in 50 million girls. It may be rare, but it does happen. We need to raise awareness for girls with Duchenne. 

Duchenne muscular dystrophy is caused by a fault, or a mutation, on the dystrophin gene. The dystrophin gene produces dystrophin protein which is required for muscle function. DMD has X-linked inheritance, this is because the dystrophin gene is on the X chromosome. Girls have two X chromosomes, one from each parent. Boys have one X chromosome, from their mother and one Y chromosome, from their father. 

Males have only one copy of the dystrophin gene. Those who inherit the mutation get the disease because they have no second dystrophin gene to produce the dystrophin protein. However, females have two copies of the dystrophin gene. When a female inherits a faulty dystrophin gene from one parent, she usually also gets a healthy dystrophin gene from the other. This usually gives her enough protein to protect her from disease. 

Manifesting carriers 

Early in embryonic development of a female, either the X chromosome from the mother or the X chromosome from the father is inactivated. This inactivation occurs randomly, so in each cell in the body, there is a 50% chance whether the maternal or paternal X chromosome will be inactivated. Usually, it doesn’t matter how many active X chromosomes from each parent a female has. However, when one X chromosome contain a mutation in a gene, such as the dystrophin gene, it can cause problems 

If a female with a dystrophin gene mutation on one of her X chromosomes has to rely on too many on the mutated X chromosomes, she is likely to develop symptoms of DMD. Usually, girls don’t experience the full effects of DMD in the way that boys do. Girls who have some signs and symptoms of DMD are called manifesting carriers. Dystrophin deficiency in these women may lead to weaker muscles in the back, legs, and arms. Manifesting carriers also often have heart problems.  

In extremely rare cases, females can develop DMD just as a boy would. This might occur a girl lacks a second X chromosome entirely or if the second X chromosome has sustained serious damage.  

A female relative of a boy with DMD, such as a mother or sister, can undergo a set of diagnostic tests to determine her carrier status. If she is a DMD carrier, regular evaluations of strength and monitoring of the heart can help manage and prevent symptoms which may develop.  

We have been speaking to Feriel, a 26 year old woman living with Duchenne muscular dystrophy. She has written us a short blog about her experiences with Duchenne from diagnosis to now.  

"My name is Feriel, I am 26 years old. I am French. I’m a woman with DMD. I was born in 1991 at six and a half months gestation. My sisters and I are triplets (two twins and a single). My twin carries the gene for DMD and my other sister has Cerebral Palsy. I started walking when I was 2 years old, but from 3 years old I started to fall over a lot. I had large calves and I walked on tiptoes. The doctors thought it was because of me being born premature and then they thought I had Cerebral Palsy like my sister.  In 1997 a doctor at Garches Hospital gave me a biopsy. Weeks later I was diagnosed with Duchenne Muscular Dystrophy, I was 6 years old. The doctor at the hospital thought that it was an error made by the genetic laboratory because this disease is very rare in women and the doctor had never seen little girls with this disease. I have a mutation stop (nonsense) of exon 12. Regarding the progression of my disease: I used a wheelchair for the first time when I was 10 years old, I lost the ability to walk after surgery on my back in 2008. In 2012 I had a lung infection. I have had bronchitis twice, once in November 2015 and the other in February 2016.  Since July 2016 I have used a breathing machine at night. When I have congestion, I use a cough assist machine. I have physiotherapy twice a week and my physiotherapist takes care of my breathing, my arms, my legs, my hands and my feet. I take medication for my heart, blood pressure, asthma, my stomach and my bones. I take a nap every day otherwise I get very tired. I do not have heart problems and my breathing capacity has increased since I started using the breathing machine. Despite having this difficult and tiring disease, I do a lot of things.  

I love traveling. I have visited Cyprus, Spain, Portugal, Malta, Italy, England, Morocco, Tunisia, Mauritania and Cuba. I am going to Senegal in February and I go to Tunisia every summer.  

I like to swim. When I swim I feel free, I feel good and the sea is good for my muscles. When I swim it is as if my disease has disappeared.   

I like watching football with my dad.  

I love singing. I do choral once a week and its good for my breathing. I like going to concerts and dancing. Music is a therapy against the disease.  

I like going to the cinema, theatre and museums.  

I like reading travel stories as they help me escape.  

In short, I love my life, my friends and my family.    

In writing this article I think about all they very strong people who have this disease, you are heroes! 

I hope a cure is found for all of us."