IN RECENT years, various classifications of the muscular dystrophies have been attempted. The classification given in Table 1 is now widely, though not universally, accepted.
Type IIIa muscular dystrophy (MD), also referred to as Duchenne pseudohypertrophic MD or the malignant form of MD, is the most frequent form. Pseudohypertrophy is occasionally found in other types of MD, notably types I and II. It is characterized by expression usually in the male (exceptionally, in the female); onset usually within the first five years of life; symmetrical involvement, first of the pelvic girdle musculature and, later, of the shoulder girdle musculature; pseudohypertrophy of muscles, particularly of the calves; steady and rapid progression, leading to inability to walk by the 12th year of life; progressive deformity from muscular contractures, skeletal distortion, and muscular atrophy; and death from inanition, respiratory tract infection and atelectasis, or cardiac failure, usually between the 15th and 25th years
Zellweger H, Hanson JW. Slowly Progressive X-Linked Recessive Muscular Dystrophy (Type IIIb): Report of Cases and Review of the Literature. Arch Intern Med. 1967;120(5):525–535. doi:10.1001/archinte.1967.00300040009002
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