General description

Hypomyelination with brainstem and spinal cord involvement and leg spasticity (HBSL) is an autosomal recessive leukodystrophy caused by pathogenic variants in the DARS1 gene, which encodes cytoplasmic aspartyl-tRNA synthetase (AspRS).

The disease typically manifests in infancy and is characterized by motor impairment, stagnation in motor development, and a decline in motor milestones. Although early development may be normal, affected individuals do not acquire independent walking. Common symptoms include spasticity, particularly in the lower limbs, ataxia, nystagmus, and, in some cases, cognitive impairment.

References

1. Taft, Ryan J., et al. "Mutations in DARS cause hypomyelination with brain stem and spinal cord involvement and leg spasticity." The American Journal of Human Genetics 92.5 (2013): 774-780.