Fatal Infantile Cardioencephalomyopathy

Due to cytochrome C oxidase deficiency

Gene: SCO2

Protein: protein SCO2 homolog, mitochondrial

Clinical Characteristics

  • Hypertrophic cardiomyopathy, onset may be several months after birth
  • Encephalopathy or Leigh syndrome (subacute necrotizing encephalopathy)
  • Lactic acidosis
  • Muscle biopsy findings:
    • Decreased activity of cytochrome c oxidase (COX deficiency)
    • Neurogenic changes or SMA-like pattern of muscle fibers
  • Hypotonia
  • Respiratory difficulty and/or inspiratory stridor
  • Developmental delay
  • Spasticity or seizures
  • Decreased extraocular movement (ptosis, strabismus)
  • History of miscarriages or stillbirths

Inheritance pattern: Autosomal recessive

What Can Be Learned From This Test

Testing is performed by sequencing the entire coding region (exon 2) and surrounding intronic regions of SCO2. 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 COX deficiency or a neuromuscular disorder, as there are many other genes, both nuclear and mitochondrial, associated with different types of neuromuscular disorders.

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: $225

Known Variant Testing

  • Code: 81403
  • Cost: $225

Download the Testing Packet

Additional Information