Typical congenital nemaline myopathy

Alternate names

Typical nemaline myopathy

Definition

Typical nemaline myopathy is a moderate neonatal form of nemaline myopathy (NM) characterized by facial and skeletal muscle weakness and mild respiratory involvement.

Epidemiology

The annual incidence of NM has been estimated at 1/50,000 live births and the typical form to represent about 50% of all cases.

Cause

Typical NM is caused by mutations of the ACTA1 (1q42.13), NEB (2q22) or TPM2 (9p13) genes.

Inheritance

The disease transmission can be autosomal recessive or dominant.

Onset

Disease onset is in the neonatal period.

Signs and symptoms

• Patients have a long face, a high-arched palate and a tented upper lip.
• Skeletal anomalies may include kyphoscoliosis, pectus carinatum and pes cavus.
• In the first year of life, hypotonia and facial weakness are present and often contribute to failure to thrive and delayed motor development.
• Anti-gravity movements are present and respiratory muscle involvement is frequent.
• Nocturnal hypoxia and hypercarbia and lower respiratory tract infections are common manifestations.
• Joint hypermobility can be observed.
• In a minority of children weakness is more distal.
• Progression is very slow or absent and most patients are able to live an independent active life.

NIH genetic and rare disease info

• NIH info on Typical congenital nemaline myopathy

Typical congenital nemaline myopathy is a rare disease.

Resources

Frequently asked questions

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