Pelvic muscle weakness and atrophy associated with pseudohypertrophy of the calves. Two basic types are recognized: Duchenne muscular dystrophy (Type I) Synonym: childhood pseudohypertrophic muscular dystrophy with the onset of symptoms between the ages of 3 and 5 years, the patients becoming bedridden by age of 12 and death by age 20 to 25 years. Becker muscular dystrophy (Type II) Synonyms: adult pseudohypertrophic muscular dystrophy mild or benign X-linked recessive muscular dystrophy with onset of symptoms between the ages of 20 and 30 years and relatively normal life expectancy in most cases. Atrophic changes begin in the muscles of the pectoral girdle and trunk and extend to the extremities. As their size increases, the muscles become firm and resilient, but their strength diminishes and, eventually, atrophy ensues. Inability to rise to an upright position without turning to the side, waddling gait, and progressive weakness are the characteristic features. Pseudohypertrophy of the calf muscles is due to fibrous tissue and fat infiltration. Involvement of the heart consists of usually terminal cardiomyopathy. Fasciculation and atrophy of the tongue with dysphagia, dysarthria, and thickened nasal speech are usually associated. Usually mild and static mental retardation occurs in about 30% DMD patients most children having normal, even superior intelligence.