Primary disorders of muscles (G71) ICD-10-CM

A group of rare genetic muscle disorders characterized by hypotonia, muscle weakness, and delayed development of motor skills.

A rare neuromuscular disorder with onset usually in late childhood or early adulthood, characterized by intermittent or continuous widespread involuntary muscle contractions; FASCICULATION; hyporeflexia; MUSCLE CRAMP; MUSCLE WEAKNESS; HYPERHIDROSIS; TACHYCARDIA; and MYOKYMIA. Involvement of pharyngeal or laryngeal muscles may interfere with speech and breathing. The continuous motor activity persists during sleep and general anesthesia (distinguishing this condition from STIFF-PERSON SYNDROME). Familial and acquired (primarily autoimmune) forms have been reported. (From Ann NY Acad Sci 1998 May 13;841:482-496; Adams et al., Principles of Neurology, 6th ed, p1491)

A group of muscle diseases associated with abnormal mitochondria function.

A heterogeneous group of inherited MYOPATHIES, characterized by wasting and weakness of the SKELETAL MUSCLE. They are categorized by the sites of MUSCLE WEAKNESS; AGE OF ONSET; and INHERITANCE PATTERNS.

A heterogenous group of inherited muscular dystrophy that can be autosomal dominant or autosomal recessive. There are many forms (called LGMDs) involving genes encoding muscle membrane proteins such as the sarcoglycan (SARCOGLYCANS) complex that interacts with DYSTROPHIN. The disease is characterized by progressing wasting and weakness of the proximal muscles of arms and legs around the HIPS and SHOULDERS (the pelvic and shoulder girdles).

An autosomal dominant degenerative muscle disease characterized by slowly progressive weakness of the muscles of the face, upper-arm, and shoulder girdle. The onset of symptoms usually occurs in the first or second decade of life. Affected individuals usually present with impairment of upper extremity elevation. This tends to be followed by facial weakness, primarily involving the orbicularis oris and orbicularis oculi muscles. (Neuromuscul Disord 1997;7(1):55-62; Adams et al., Principles of Neurology, 6th ed, p1420)

A group of inherited congenital myopathic conditions characterized clinically by weakness, hypotonia, and prominent hypoplasia of proximal muscles including the face. Muscle biopsy reveals large numbers of rod-shaped structures beneath the muscle fiber plasma membrane. This disorder is genetically heterogeneous and may occasionally present in adults. (Adams et al., Principles of Neurology, 6th ed, p1453)

Inherited myotonic disorders with early childhood onset MYOTONIA. Muscular hypertrophy is common and myotonia may impair ambulation and other movements. It is classified as Thomsen (autosomal dominant) or Becker (autosomal recessive) generalized myotonia mainly based on the inheritance pattern. Becker type is also clinically more severe. An autosomal dominant variant with milder symptoms and later onset is known as myotonia levior. Mutations in the voltage-dependent skeletal muscle chloride channel are associated with the disorders.

Diseases characterized by MYOTONIA, which may be inherited or acquired. Myotonia may be restricted to certain muscles (e.g., intrinsic hand muscles) or occur as a generalized condition.

Neuromuscular disorder characterized by PROGRESSIVE MUSCULAR ATROPHY; MYOTONIA, and various multisystem atrophies. Mild INTELLECTUAL DISABILITY may also occur. Abnormal TRINUCLEOTIDE REPEAT EXPANSION in the 3' UNTRANSLATED REGIONS of DMPK PROTEIN gene is associated with Myotonic Dystrophy 1. DNA REPEAT EXPANSION of zinc finger protein-9 gene intron is associated with Myotonic Dystrophy 2.

Deficiencies or mutations in the genes for the SARCOGLYCAN COMPLEX subunits. A variety of phenotypes are associated with these mutations including a subgroup of autosomal recessive limb girdle muscular dystrophies, cardiomyopathies, and respiratory deficiency.

A classification for rare genetic syndromes with an autosomal recessive pattern of inheritance. Clinical features include muscle stiffness and weakness, facial and skeletal abnormalities with joint contractures and short stature. Two types have been characterized: Schwartz-Jampel Syndrome type I (SJSI) and Schwartz-Jampel Syndrome type II (SJSII). SJSI is associated with a mutation of the HSPG2 gene on chromosome 1 and has been further characterized into two subtypes IA and IB. SJSIA is more common, less severe in presentation and is seen later in childhood than SJSIB. For both SJSI subtypes, prognosis is favorable as the main feature of muscle stiffness is slowly progressive, if at all, and is compatible with a normal life span. SJSII is apparent at birth, shares the same clinical profile and mutation in the LIFR gene noted in Stuve-Wiedemann Syndrome and is thus presumed to be the same disorder. In contrast to SJSI, its presentation is more severe and likelihood of survivability is much lower.

An X-linked recessive inherited disorder caused by mutations in the MTM1 gene. Primarily it affects males. Female carriers are usually asymptomatic. It is characterized by skeletal muscle weakness and hypotonia. The muscle weakness ranges from mild to severe. Newborns with severe X-linked centronuclear myopathy develop respiratory distress which may lead to respiratory failure requiring constant ventilator assistance. Patients with mild X-linked centronuclear myopathy usually require ventilator support during the newborn period only.

Of the 35 codes in this range, 28 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.

The range classifies primary disorders of muscles. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.