MedGen

Severe weight loss, wasting of muscle, loss of appetite, and general debility related to a chronic disease. [from HPO]

Any weakening or degeneration, especially through lack of use. [from NCI]

Myostatin-related muscle hypertrophy is a rare condition characterized by reduced body fat and increased muscle size. Affected individuals have up to twice the usual amount of muscle mass in their bodies. They also tend to have increased muscle strength. Myostatin-related muscle hypertrophy is not known to cause any medical problems, and affected individuals are intellectually normal. [from MedlinePlus Genetics]

Abnormal increase in muscle size and mass not due to training. [from HPO]

The presence of skeletal muscular atrophy (which is also known as amyotrophy). [from HPO]

A group of disorders that affect the neuromuscular system. They may be acquired or inherited and tend to be progressive, resulting in debilitating muscle weakness. [from NCI]

A disorder of muscle unrelated to impairment of innervation or neuromuscular junction. [from HPO]

A non-neoplastic or neoplastic disorder that affects muscles and bones. [from NCI]

A rare vascular anomaly with the association of capillary and venous malformations with hypotrophy or shortening of an affected limb due to alterations in bones, muscles, or subcutaneous tissues. In most cases, at least one of the findings is noted shortly after birth, while the other components become evident later in infancy. [from SNOMEDCT_US]

Atrophy (wasting) affecting primary type 1 muscle fibers. This feature in general can only be observed on muscle biopsy. [from HPO]

Wasting of the tibialis anterior muscle. [from HPO]