What Can Be Learned From This Test
The diagnosis of MLC is based on diagnostic criteria, including brain MRI. A negative test result does not rule out a diagnosis of MLC since a mutation may not be identifiable with test methods used, or a mutation may be in another gene. This test will only detect mutations in MLC1 and HEPACAM.
Mutations in MLC1 and HEPACAM are found in 75 percent and 20 percent of affected individuals, respectively. Testing can be performed in tiers, moving to the next tier only if the preceding test is negative. Testing can also be performed concurrently, or in any order requested.
The following strategy is suggested:
- Tier 1 sequencing of untranslated exon 1 and the entire coding region of MLC1
- Tier 2 sequencing of the entire coding region of HEPACAM
This will detect point mutations, small deletions, and small insertions. It will not detect a partial or whole gene deletion or duplication. Sequencing will identify the majority of mutations, but partial gene deletions have been reported in MLC1 (Ilja Boor et al, 2006).
Draw 2ml–4ml of blood in EDTA/purple-top tube (minimum of 1ml–2ml for infants).
Turnaround time: 10-14 business days per tier
CPT Codes and Cost
Full Gene Sequencing
Known Variant Testing