Slowly progressive proximal weakness: limb-girdle syndromes.

Many diseases of the motor unit result in slowly progressive limb-girdle weakness. Difficulty in diagnosis arises because many of these disorders share a similar genetic pattern, and some are heterogeneous. Most of the symptoms have such a broad range that they are of limited diagnostic value, and physical findings, even within families, often cover a wide spectrum. With a few exceptions, laboratory data are often of only limited diagnostic assistance. This review documents the need for a careful genetic, clinical, and laboratory evaluation in these disorders, affirms the importance of clinical observation, and identifies the most dependable clinical and laboratory findings.