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14 | InTouch AUTUMN 2025 DUCHENNE MUSCULAR DYSTROPHY (DMD) Manifesting Carriers of DMD It is a commonly held belief that carriers merely pass on a condition and are unaffected, however approximately 10% of female carriers show symptoms of DMD. Although the disorder in affected girls is usually much milder than in boys and may include or even exclusively affect cognitive and/or cardiac function, a few girls do have DMD similar in severity to boys. In girls, each cell has two X chromosomes, which contain the genetic instructions for making dystrophin. Normally, each cell will “turn off” one of these X chromosomes. If the X chromosome with the healthy dystrophin gene is turned off, the cell can’t produce dystrophin. This can cause some girls, called “manifesting carriers,” to show symptoms similar to boys with DMD. The severity of symptoms in these girls depends on how many of their cells have the working dystrophin gene turned on. Diagnosis of DMD The possibility of DMD should be considered in boys who show certain symptoms, even if there is no family history of the condition. Key signs include abnormal muscle function, like difficulty walking or getting up from the floor. Additionally, if a boy uses his hands to “climb up” his legs to stand (known as Gowers’ sign) or walks with a side-to-side motion (waddling gait), it should prompt further investigation for DMD. Toe walking might occur, but it’s not as useful in identifying DMD. Sometimes, DMD is suspected after blood tests show high levels of certain enzymes, such as creatine kinase (produced by muscle) or aspartate aminotransferase and alanine aminotransferase (produced by muscle and liver). The elevation of these enzymes is due to muscle breakdown rather than a problem with the liver. When there is a positive family history of DMD, there should be a low threshold for testing creatine kinase, although this will be influenced by the age of the child. In a child less than 5 years of age, suspicion of DMD probably cannot be excluded completely by a normal muscle examination. However, with increasing age, a normal muscle examination makes the chance of a child having DMD less and less likely. A boy older than 10 years of age with normal muscle function is unlikely to have DMD. Confirmation of a Diagnosis To diagnose DMD, doctors can use a blood test to look for specific genetic changes in the dystrophin gene. If they find these changes, it confirms the diagnosis. However, sometimes the specific genetic change can’t be found, even if DMD is present. This doesn’t mean the child doesn’t have DMD, just that the exact error is difficult to identify. If DMD is suspected but the genetic test doesn’t give clear results, a muscle biopsy might be needed. In a muscle biopsy, a small sample of muscle tissue is taken to see how much dystrophin protein is present. This information helps determine if the problem is DMD or another condition affecting the muscle integrity. Management of DMD The management of DMD has significantly evolved over the past two decades. Advances in clinical monitoring, improved management of heart and lung complications, and better nutritional strategies have all contributed to enhanced quality of life and longer life expectancy for those affected. Ongoing research continues to drive further improvements in care. Children with DMD should be under the care of a paediatric neurologist who can refer to other medical disciplines as required. Clinical assessments should be performed regularly to monitor function. Medical Management : Steroids, also known as glucocorticoids or corticosteroids, are currently the only medications proven to slow the decline in muscle strength and motor function in DMD. The primary goal of steroid therapy is to prolong independent walking, enhance participation in daily activities, and reduce future complications related to breathing, heart function, and The management of Duchenne Muscular Dystrophy (DMD) has significantly evolved over the past two decades. Continued from previous page.