LIG4-Related Disorders

Gene: LIG4

Protein: DNA ligase 4

Clinical Characteristics

  • Pancytopenia
  • Immunodeficiency, sensitivity to ionizing radiation
  • Microcephaly
  • Developmental delay
  • Growth delay
  • Increased risk for malignancies including leukemia and lymphoma
  • Can have severe combined immunodeficiency (SCID) and/or radiosensitivity without other features
  • Characteristic facial features:
    • Similar to Seckel syndrome
    • Low anterior hairline
    • Prominent or broad nasal bridge
    • Epicanthal folds

Inheritance pattern: Autosomal recessive

What Can Be Learned From This Test

Testing is performed by sequencing both exons of the LIG4 gene as well as partial intronic regions. This will detect point mutations, small deletions and small insertions. It will not detect a partial or whole gene deletion or duplication. To date, no large deletions or duplications have been reported.

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: $350

Known Variant Testing

  • Code: 81479
  • Cost: $225

Additional Information