Cuban epidemic optic neuropathy. Mitochondrial DNA analysis

Area of Science:

• Neuroscience
• Genetics
• Ophthalmology

Background:

• Leber's hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disease.
• Cuban epidemic optic neuropathy (CEON) presented as an epidemic and shares some clinical similarities with LHON.
• The genetic basis of CEON remained unclear, prompting investigation into mitochondrial DNA (mtDNA) mutations.

Purpose of the Study:

• To determine if known Leber's hereditary optic neuropathy (LHON)-associated mitochondrial DNA (mtDNA) mutations are present in patients with Cuban epidemic optic neuropathy (CEON).
• To investigate the potential genetic contribution of mtDNA mutations to the etiology of CEON.

Main Methods:

• Neuro-ophthalmologic examinations were performed on 12 CEON patients and 1 LHON patient.
• Blood samples were collected from CEON patients, an LHON patient, and 3 controls.
• Molecular genetic methods were used to screen for 9 specific LHON-associated mtDNA mutations.

Main Results:

• Cuban epidemic optic neuropathy (CEON) patients exhibited distinct clinical and epidemiological features compared to typical Leber's hereditary optic neuropathy (LHON).
• None of the 12 CEON patients or 3 controls carried any of the 9 screened LHON-associated mtDNA mutations.
• The single patient with clinical LHON harbored the 11778 mtDNA mutation, but did not meet the CEON case definition.

Conclusions:

• Frequently identified Leber's hereditary optic neuropathy (LHON) mitochondrial DNA (mtDNA) mutations are not a common cause of Cuban epidemic optic neuropathy (CEON).
• CEON may result from acquired mitochondrial dysfunction due to nutritional deficiencies or toxins, or potentially from undiscovered mtDNA mutations.
• Further research is needed to elucidate the specific genetic and environmental factors contributing to CEON.