Characteristics of the test: (includes 3 genes)

MT-ND1 (OMIM #516000)

MT-ND4 (OMIM #516003)

MT-ND6 (OMIM #516006)

Basic characteristics of the clinical phenotype

Leber's hereditary optic neuropathy (LHON) is an inherited form of vision loss. The onset is usually in the teenage years, but cases with earlier or later onset are also known. The disease is thought to affect men more often than women.

Mutations in the MT-ND1 (OMIM #516000), MT-ND4 (OMIM #516003), and MT-ND6 (OMIM #516006) genes are responsible for over 95% of LHON cases.

Reasons for referring:
Candidates for this test are all patients with symptoms of Leber's Hereditary Optic Neuropathy or another mitochondrial disease, as well as relatives of patients in whom the mutation is known.

Interpretation of results:
· Identification of point mutations and small deletions/insertions in the MT-ND1, MT-ND4 and MT-ND6 genes will allow a genetic diagnosis of Leber Hereditary Optic Neuropathy.

· Presence of large deletions and insertions cannot be detected by this method. A combination with a suitable CNV analysis (MLPA, aCGH) is recommended for their detection.

· The genetic counselor will interpret and answer all questions about your result.

Method: Sanger sequencing.
The method involves bi-directional DNA sequencing of the MT-ND1, MT-ND4 and MT-ND6 genes. The laboratory offers single gene sequencing in relatives of patients to determine carrier status in cases where the mutation is known (Test #182).

Sensitivity of the method: 99.5%

What does the test involve?
· DNA isolation and sample storage.
· Direct sequencing of target genes/gene regions to detect pathogenic mutations.
· Forming a written result of the genetic test.
· Diagnostic interpretation of results and genetic counseling.

Biological material: Venous blood or DNA

For more information, please read the "Biological material requirements and shipping information" carefully.