Torticollis is a twisted neck as a result of shortening of sternocleidomastoid muscle. This short and fibrotic muscle pulls the head laterally and rotates the chin and face to the opposite end. Facial asymmetry may be a manifestation (summary by Engin et al., 1997).

A type of Developmental delay characterized by a delay in acquiring motor skills.

Subnormal intellectual functioning which originates during the developmental period. Intellectual disability, previously referred to as mental retardation, has been defined as an IQ score below 70.

Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.

The presence of an abnormal lateral curvature of the spine.

Reduced strength of muscles.

A phenomenon whereby patients are not able to stand up without the use of the hands owing to weakness of the proximal muscles of the lower limbs.

The presence of skeletal muscular atrophy (which is also known as amyotrophy).

Congenital muscular dystrophy (CMD) is a heterogeneous group of neuromuscular disorders with onset at birth or infancy characterized by hypotonia, muscle wasting, weakness or delayed motor milestones. The group includes myopathies with abnormalities at different cellular levels: the extracellular matrix (MDC1A, UCMD; see these terms), the dystrophin-associated glycoprotein complex (alphadystroglycanopathies, integrinopathies see these terms), the endoplasmic reticulum (rigid spine syndrome [RSMD1], and the nuclear envelope (LMNA-related CMD; [L-CMD] and Nesprin-1-related CMD; see these terms).

An abnormally high degree of muscle fiber size variation. This phenotypic feature can be observed upon muscle biopsy.

Muscle fibers degeneration resulting in fatty replacement of skeletal muscle fibers

An elevation of the level of the enzyme creatine kinase (also known as creatine phosphokinase (CK; EC 2.7.3.2) in the blood. CK levels can be elevated in a number of clinical disorders such as myocardial infarction, rhabdomyolysis, and muscular dystrophy.