FAQs

LHON is a rare genetic condition that leads to symptoms such as sudden sight loss and blurred vision. These are caused by mutations in the mitochondrial DNA. A mother with an LHON mutation passes it on to all her children. However, a father who has LHON cannot pass it on to any of his children. This is because the mitochondria for the developing baby come from the mother’s egg cells and not the father’s sperm cells.

A second form of LHON mutation in a nuclear encoded gene, DNAJC30, has also been established—described as an autosomal recessive mode of inheritance for LHON.

LHON is a progressive disease leading to severe vision impairment. Most patients with LHON become legally blind. Some people with LHON have experienced partial recovery of sight in one or both eyes. Speak to a neuro-ophthalmologist if you have symptoms or a family history of LHON. They can guide you on the possible options, such as treatment, follow up, and low vision rehabilitation.

People without a family history of LHON are known to develop the condition. Around one in three cases appears to be sporadic with no definitive family history. In addition, a second form of LHON mutation in a nuclear encoded gene, DNAJC30, has also been established—described as an autosomal recessive mode of inheritance for LHON (arLHON).

If the ophthalmologic assessments and molecular genetic testing leave any uncertainty about the diagnosis of LHON, further investigations are appropriate to exclude other potentially reversible causes of bilateral optic neuropathy. Timely intervention allows you and your family to access the full range of supportive care options.

Molecular genetic testing approaches can include a combination of gene-targeted testing methods such as targeted mtDNA analysis for pathogenic variants, multigene panel, and complete mtDNA sequencing. Clinical diagnosis for nuclear mutations such as arLHON can be performed through patient-derived fibroblast cell lines obtained by skin biopsy.⁶

The threat of acquiring LHON never goes away but you can avoid certain lifestyle factors to reduce the risk. Those with an LHON mutation are advised to stop smoking, moderate their alcohol intake and avoid certain drugs. Men are three times more likely to be affected by LHON than women. The first signs of vision loss usually appear between the ages of 15 and 35 years. In rare cases, patients as young as 2 years of age and as old as 87 years of age have experienced symptoms. LHON affects women more commonly during the menopause years.

A mother with an LHON mutation passes it on to all her children. However, a father who has LHON cannot pass it on to any of his children. This is because the mitochondria for the developing baby come from the mother’s egg cells and not the father’s sperm cells. So, any mutations in the mitochondria can only be inherited maternally.

However, around one in three cases also appears to be sporadic with no definitive family history. In addition, a second form of LHON mutation in a nuclear encoded gene, DNAJC30, has also been established—described as an autosomal recessive mode of inheritance for LHON.

For patients and their families, LHON can come as a shock. However, most of the affected people adjust to their new level of visual functioning within a few years after the first symptoms of LHON appear. There are a number of patient advocacy groups and online support groups for patients with LHON, such as LHON.org, lhonsociety.org, and visionhopenow.org.