SMALED2A is an autosomal dominant form of spinal muscular atrophy characterized by early childhood onset of muscle weakness and atrophy predominantly affecting the proximal and distal muscles of the lower extremity, although some patients may show upper extremity involvement. The disorder results in delayed walking, waddling gait, difficulty walking, and loss of distal reflexes. Some patients may have foot deformities or hyperlordosis, and some show mild upper motor signs, such as spasticity. Sensation, bulbar function, and cognitive function are preserved. The disorder shows very slow progression throughout life (summary by Oates et al., 2013).
For discussion of genetic heterogeneity of lower extremity-predominant spinal muscular atrophy, see SMALED1 (158600). [from OMIM]
- MedGen UID:
- 1669929
- •Concept ID:
- C4747715
- •
- Disease or Syndrome