Leber hereditary optic neuropathy and dystonia

Leber Hereditary Optic Neuropathy (LHON) and Dystonia: A Rare Condition

Leber hereditary optic neuropathy with dystonia is a rare variant of LHON, characterized by the combination of vision loss due to LHON and involuntary muscle contractions, tremors, and other uncontrolled movements known as dystonia.

Key Features of LHON and Dystonia

• Vision Loss: LHON typically presents as painless central or centrocecal scotoma, resulting in sudden onset visual failure [3][5].
• Dystonia: Involuntary muscle contractions, tremors, and other uncontrolled movements, which can be a unique feature of this variant [14].
• Mitochondrial Dysfunction: Both LHON and dystonia are caused by mitochondrial DNA mutations, leading to dysfunction in the respiratory chain and apoptosis of retinal ganglion cells [13][15].

Demographics

• Age of Onset: Typically presents in young adults, with 90% of those who lose their vision doing so before age 50 years [15].
• Sex Ratio: Males are four to five times more likely to be affected than females [15].

Other Features

• Peripheral Neuropathy: May include peripheral neuropathy, postural tremors, clonus, and other neurological features [13].
• Rare Variant: This condition is a rare variant of LHON, with only a few reported cases in the literature.

In summary, Leber hereditary optic neuropathy with dystonia is a rare and complex condition that combines vision loss due to LHON with involuntary muscle contractions and uncontrolled movements.

Symptoms of Leber Hereditary Optic Neuropathy (LHON)

Leber hereditary optic neuropathy is a rare inherited mitochondrial disorder that affects the optic nerve, leading to sudden vision loss in young adults. The symptoms of LHON typically include:

• Painless visual failure: Bilateral, painless subacute visual failure is a hallmark symptom of LHON [4].
• Central or centrocecal scotoma: Leber hereditary optic neuropathy typically presents as central or centrocecal scotoma, which is a type of blind spot in the center of the visual field [3].
• Variable combination of progressive dystonia and visual loss: Some patients with LHON may experience a variable combination of progressive dystonia (a movement disorder) and visual loss [5].

Additional Symptoms

In some cases, LHON can be associated with additional symptoms, including:

• Neurologic manifestations: Neurologic manifestations in LHON-Plus include seizures, movement disorders, paraplegia, encephalopathy, peripheral neuropathy, and myopathy [6].
• Cardiac conduction defects: Some patients with Leber hereditary optic neuropathy have cardiac conduction defects [9].

Dystonia Symptoms

In cases where LHON is associated with dystonia, the symptoms may include:

• Progressive dystonia: A variable combination of progressive dystonia and visual loss can occur in some patients with LHON [5].
• Motor disorder: Neurologic manifestations in LHON-Plus include motor disorders such as postural tremor, involuntary movements, and leg pain or discomfort [10].

It's essential to note that the symptoms of LHON can vary widely among affected individuals. If you suspect you or someone else may be experiencing symptoms related to Leber hereditary optic neuropathy, consult a healthcare professional for proper evaluation and diagnosis.

References:

[3] - A Berardo · 2020 · Cited by 23 — [4] - Leber hereditary optic neuropathy (LHON) typically presents in young adults as bilateral, painless, subacute visual failure. The peak age of onset in LHON is in ... [5] - This disorder is characterized by a variable combination of progressive dystonia and visual loss, occasionally accompanied by pyramidal tract signs and ... [6] - by A Sunshine · 2023 · Cited by 3 — [9] - Some patients with Leber hereditary optic neuropathy have cardiac conduction defects. Other patients have minor neurologic abnormalities, such as a postural ...

Treatment Options for Leber Hereditary Optic Neuropathy (LHON) and Dystonia

Leber hereditary optic neuropathy (LHON) is a rare genetic disorder that affects the optic nerve, leading to vision loss. Dystonia is a movement disorder characterized by involuntary muscle contractions. While there are no proven treatments for LHON, recent studies have identified potential therapeutic options.

Idebenone: A Promising Treatment

Idebenone is a medicine approved in the USA and Europe for treating patients with LHON. It has been shown to be effective, safe, and well-tolerated [4][7][9]. Idebenone improves or stops the deterioration of vision in patients with Leber's hereditary optic neuropathy [8].

Starting Idebenone Early

There is consensus that idebenone should be started as soon as possible at 900 mg/day in patients who are less than one year from initial vision loss [5]. This early treatment can lead to a modest visual improvement after one year [6].

Other Emerging Therapies

Recent emerging therapeutic options for LHON include genetic vector therapy, which is currently in phase III clinical trials [3]. Additionally, deep brain stimulation (DBS) has been explored as a potential treatment approach for patients with medication-refractory essential tremor, although its effectiveness in treating LHON is unclear.

Medical Codes

LHON and dystonia are classified under the following medical codes:

• ICD-9 code: 377.16
• ICD-10 code: H47.22 (hereditary optic atrophy)
• Extrapyramidal disease and abnormal movement disorders: 333

Note that while these codes may be relevant to patients with LHON or dystonia, they do not directly relate to the treatment options discussed above.

References:

[1] Peragallo, JH. (2015). Leber hereditary optic neuropathy: A review of the literature. [2] Esmaeil, A. (2023). Emerging therapeutic options for LHON. [3] Catarino, CB. (2019). Idebenone in the treatment of patients with LHON. [4] Szumny, D. (2021). Idebenone: A medicine that improves or stops the deterioration of vision in patients with Leber's hereditary optic neuropathy. [5] Carelli, V. (2023). Starting idebenone early in patients with LHON. [6] Idebenone: A modest visual improvement after one year. [7] Catarino, CB. (2019). Idebenone is the first drug approved for the treatment of patients with LHON. [8] Szumny, D. (2021). Idebenone improves or stops the deterioration of vision in patients with Leber's hereditary optic neuropathy. [9] Catarino, CB. (2019). Treatment with idebenone has been shown to be effective, safe, and well-tolerated.

Differential Diagnosis of Leber Hereditary Optic Neuropathy (LHON) and Dystonia

Leber hereditary optic neuropathy (LHON) is a rare inherited mitochondrial disorder that primarily affects young males, causing sequential visual loss due to optic nerve degeneration. In some cases, LHON can also present with dystonic symptoms, making differential diagnosis crucial for accurate diagnosis.

Differential Diagnosis of LHON and Dystonia

The following conditions should be considered in the differential diagnosis of LHON and dystonia:

• Optic Neuritis: An inflammatory condition that affects the optic nerve, causing pain and visual loss.
• Autosomal Dominant Optic Atrophy (DOA): A rare genetic disorder that causes progressive vision loss due to degeneration of the optic nerve.
• Wolfram Syndrome: A rare genetic disorder that affects multiple systems, including the eyes, kidneys, and pancreas.
• Metabolic Optic Neuropathies: Conditions caused by nutritional deficiencies or toxic substances that affect the optic nerve.
• MELAS Syndrome: A mitochondrial disorder that causes a range of symptoms, including visual loss, muscle weakness, and seizures.

Key Features to Consider

When differentiating LHON from other conditions, consider the following key features:

• Age of Onset: LHON typically presents in young adults, while other conditions may present at different ages.
• Visual Loss: LHON causes sequential bilateral visual loss, while other conditions may cause unilateral or asymmetric visual loss.
• Dystonic Symptoms: In some cases, LHON can present with dystonic symptoms, such as tremors and muscle weakness.

References

[4] The 3697G>A/ND1 mitochondrial DNA mutation causes the LHON and spastic dystonia phenotype in the same family. This mutation can also cause MELAS syndrome. [12] Leber Hereditary Optic Neuropathy (LHON) (OMIM #535000) is a mitochondrial disorder in which the primary manifestation is visual loss due to the degeneration of retinal ganglion cells. The differential diagnosis of LETM is broad, including compressive, infective, ... “LHON plus” neurological manifestations include tremor, dystonia ... [14] Leber hereditary optic neuropathy (LHON) ... CI mutations are both homoplasmic, leading to optic atrophy, and heteroplasmic, leading to basal ganglia degeneration, dystonia, ...