Inherited and progressive myopathy affecting boys. Affected individuals present with muscular, respiratory, and cardiac disease. The cardiac and orthopedic complications (ie, scoliosis) are present in most cases. The presence of myotonia/hypotonia usually begins around the age of four in boys and worsens rapidly. The muscle groups affected are typically upper legs and pelvis followed by the upper arms. Young boys affected are unable to walk by the age of 12 years. Death usually occurs in the twenties due to respiratory muscle weakness or cardiomyopathy. Intellectual disability is often associated. Females may show mild symptoms but maintain a normal life expectancy.
DMD Syndrome; Pseudohypertrophic Muscular Dystrophy; Duchenne Type Progressive Muscular Dystrophy; Progressive Muscular Dystrophy Type I.
This medical condition was first described by Giovanni Semmola (1793-1865), a Neapolitan Italian physician, in 1834 and subsequently characterized by Gaetano Conte, physician and professor in the Ospedale degli Incurabili of Naples Italy, in 1836. During a meeting held in S. Agnello di Sorrento, Naples, in 1991, the Gaetano Conte Prize was established in order to remember this important step in the knowledge of muscle diseases, and ever since that event, the prize has been awarded, at each Congress of the Mediterranean Society of Myology (MSM), to the scientists, working in clinical or in basic sciences or in the social field, who had contributed to the progress of knowledge on muscular diseases. However, the disease is named after the French neurologist Guillaume-Benjamin-Amand Duchenne (1806-1875), who in the 1861 edition of his book Paraplegie hypertrophique de l’enfance de cause cerebrale, described and detailed the case of a boy who had this condition. A year later, he presented photos of his patient in his Album de photographies pathologiques. In 1868, he gave an account of 13 other affected children. Duchenne was the first to do a biopsy to obtain tissue from a living patient for microscopic examination.
The incidence has been established at approximately 1:3500 to 5000 males at birth. It is the most common form of muscular dystrophy. There is no ethnic preference or nationality associated with this condition. The average life expectancy is 26 years of age but with excellent care, it has been reported as long as the fourth or early fifth decades. The disease affects almost exclusively males, although females rarely can be affected, for example, when they have a translocation between autosomal chromosomes and the X chromosome, uniparental disomy (ie, when the chromosome pair or specific segments of a chromosome pair are inherited from one parent only), or suffer from Turner Syndrome.
About one-third results from spontaneous mutation (negative family history does not exclude DMD); the rest is inherited in an X-gonosomal recessive way. Simplified, in DMD a frameshift mutation results in ...