Hypomyelinating Leukodystrophy 9

Gene: RARS1

Protein: arginine--tRNA ligase, cytoplasmic

Clinical Characteristics

  • Delayed motor development
  • Spasticity
  • Nystagmus
  • Onset in the first year of life
  • Diffuse hypomyelination affecting all regions of the brain
  • Ataxia and dystonia may be present
  • Mild intellectual disability may be present
  • Phenotype is variable and severe symptoms with early brain atrophy have been reported

Inheritance pattern: Autosomal recessive

What Can Be Learned From This Test

Testing is performed by sequencing the entire coding region and surrounding intronic regions of RARS1. This will detect point mutations, small deletions, and small insertions. It will not detect a partial or whole gene deletion or duplication.

A negative test does not rule out a genetic cause of hypomyelinating leukodystrophy. There may be a mutation in a region of the RARS1 gene not analyzed, or a partial or whole gene deletion or duplication.

Mutations in multiple other genes are known to cause other forms of hypomyelinating leukodystrophy. Testing of other genes associated with hypomyelinating leukodystrophy is available in our laboratory and can be performed if clinically indicated.

Sample Requirements

Draw 2ml–4ml of blood in EDTA/purple-top tube (minimum of 1ml–2ml for infants).

Turnaround time: 10–14 business days

CPT Codes and Cost

Full Gene Sequencing

  • Code: 81479
  • Cost: $900

Known Variant Testing

  • Code: 81479
  • Cost: $225

Additional Information