Washington, June 23 : The US Food and Drug Administration (FDA) on Friday announced the approval of Elevidys -- the first gene therapy for the treatment of children aged 4 and 5 years with Duchenne muscular dystrophy (DMD). The therapy from biotech company Sarepta Therapeutics will be administered as a single intravenous dose in children with a confirmed mutation in the DMD gene who do not have a pre-existing medical reason preventing treatment with this therapy, the agency said. According to the company, the drug would cost $3.2 million per patient. DMD is a rare and inherited disorder of progressive muscular weakness, typically seen in boys (about one in every 3,300 boys), while girls can be carriers and are mildly affected. Symptoms include frequent falls, trouble getting up or running, waddling gait, big calves and learning disabilities. Patients often succumb to the disease in their 20s or 30s because of heart and/or respiratory failure. The disease occurs due to a defective gene that results in absence of dystrophin, a protein that helps keep the body's muscle cells intact. The new Elevidys is a recombinant gene therapy designed to deliver into the body a gene that leads to production of micro-dystrophin -- a shortened protein that contains selected domains of the dystrophin protein present in normal muscle cells. The FDA granted approval based on study results which established that Elevidys increased the expression of the Elevidys micro-dystrophin protein observed in children aged 4 to 5 years with DMD. However, since a clinical benefit of Elevidys, including improved motor function, has not been established the FDA has required the company to complete a clinical study as a condition of approval. The ongoing study is designed to assess whether Elevidys improves physical function and mobility in ambulatory DMD patients with a confirmed mutation in the DMD gene. The agency will review the data from this trial as quickly as possible to consider if further action, such as a revised indication or withdrawal of Elevidys, may be necessary. "Today's approval addresses an urgent unmet medical need and is an important advancement in the treatment of Duchenne muscular dystrophy, a devastating condition with limited treatment options, that leads to a progressive deterioration of an individual's health over time," said Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, in a statement. "The FDA remains committed to facilitating the development of innovative new therapies to reduce the impact of debilitating diseases and to improve outcomes and quality of life for those affected," he added. /IANS