GTR Home > Conditions/Phenotypes > Spinal muscular atrophy, lower extremity predominant 1, autosomal dominant


Spinal muscular atrophy (SMA) is a hereditary neuromuscular disorder characterized by degeneration of spinal cord motor neurons resulting in muscle weakness. SMALED shows autosomal dominant inheritance with muscle weakness predominantly affecting the proximal lower extremities (Harms et al., 2010). The most common form of SMA (see, e.g., SMA1, 253300) shows autosomal recessive inheritance and is due to mutation in the SMN1 gene (600354) on chromosome 5q. Genetic Heterogeneity of Lower Extremity-Predominant Spinal Muscular Atrophy See also SMALED2 (615290), caused by mutation in the BICD2 gene (609797) on chromosome 9q22. [from OMIM]

Available tests

4 tests are in the database for this condition. Compare labs offering these tests.

Check Associated genes for additional relevant tests.

Associated genes

  • Also known as: DHC1, DHC1a, DNCH1, DNCL, DNECL, DYHC, Dnchc1, HL-3, SMALED1, p22, DYNC1H1
    Summary: dynein, cytoplasmic 1, heavy chain 1

Clinical features

  • Waddling gait
  • Difficulty running
  • Proximal muscle weakness in lower limbs
  • Decreased patellar reflex
  • Type 2 muscle fiber predominance
  • Abnormality of the foot
  • EMG: neuropathic changes
  • Sensory impairment
  • Spinal muscular atrophy
  • Proximal lower limb amyotrophy
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