familial hemiplegic migraine 3

Familial Hemiplegic Migraine 3 (FHM3): A Rare and Severe Subtype

Familial hemiplegic migraine-3 (FHM3) is a rare subtype of migraine with aura, characterized by some degree of hemiparesis (weakness on one side of the body) during attacks. This condition is caused by genetic changes in the SCN1A gene [5].

Key Features:

• A severe subtype of migraine with aura
• Characterized by focal neurological symptoms such as sensory and motor disturbances [2]
• Hemiparesis or weakness on one side of the body during attacks [5, 10]
• Rare type of migraine with aura [2]

Diagnosis: FHM3 is diagnosed if no genetic change currently known to cause FHM can be identified. This subtype is often associated with a family history of similar symptoms [4].

References:

[1] Not applicable (no relevant information in search results)

[2] Context 2, Context 9

[3] Not applicable (no relevant information in search results)

[4] Context 4

[5] Context 5

[6] Context 6

[7] Not applicable (no relevant information in search results)

[8] Context 8

[9] Context 2, Context 9

[10] Context 10

Familial Hemiplegic Migraine (FHM) Signs and Symptoms

Familial hemiplegic migraine (FHM) is a rare type of migraine that can cause significant symptoms. The signs and symptoms of FHM can vary from person to person, but they often include:

• Weakness on one side of the body: This is the most common symptom of FHM, and it can range from mild weakness to complete paralysis.
• Ataxia: Ataxia refers to a lack of coordination or balance. People with FHM may experience ataxia, which can make it difficult to walk or perform other physical tasks.
• Coma: In some cases, FHM can cause a coma, which is a state of deep unconsciousness.
• Paralysis: Paralysis is another possible symptom of FHM, and it can be temporary or permanent.
• Migraine attacks: People with FHM often experience migraine attacks, which can be triggered by minor head trauma.

These symptoms can last for hours, days, or even weeks in some cases. It's essential to seek medical attention if you're experiencing any of these symptoms, as they can be a sign of a more serious underlying condition.

References:

• [3] Familial hemiplegic migraine (FHM) is an autosomal dominant type of hemiplegic migraine that typically includes weakness of half the body which can last for hours, days, or weeks. It can be accompanied by other symptoms, such as ataxia, coma, and paralysis.
• [5] Hemiplegic migraine is a rare disorder in which affected individuals experience a migraine headache along with weakness on one side of the body ...
• [6] Familial hemiplegic migraine (FHM) is defined by migraine with aura and motor weakness and at least one first- or second-degree relative with migraine aura and ...

Familial Hemiplegic Migraine Type 3 (FHM3) can be diagnosed through various diagnostic tests.

• Genetic testing: A genetic test can confirm the presence of a mutation in the SCN1A gene, which is associated with FHM3 [7].
• Imaging studies: Imaging studies such as CT scans and MRI scans may be performed to rule out other potential conditions that may cause similar symptoms [6].
• Lumbar puncture: A lumbar puncture (LP) may also be performed to collect cerebrospinal fluid for analysis, which can help confirm the diagnosis of FHM3.
• Multigene panel testing: Multigene panel testing, such as the Invitae Familial Hemiplegic Migraine Panel, analyzes genes associated with familial hemiplegic migraine (FHM), including CACNA1A, ATP1A2, and SCN1A [5].
• Exome sequencing: Exome sequencing may also be performed to identify genetic mutations that can cause FHM3.

It's worth noting that a diagnosis of FHM3 typically requires a combination of clinical evaluation, family history, and genetic testing. A doctor may suggest additional tests to confirm the diagnosis and rule out other potential conditions [3].

References: [3] - The clinical diagnosis of FHM can be established in a proband: (1) who fulfills criteria for migraine with aura; (2) in whom the aura includes fully reversible motor weakness and visual, sensory or language symptoms; and (3) who has at least one first- or second-degree relative with similar attacks that fulfill the diagnostic criteria for hemiplegic migraine. [5] - The Invitae Familial Hemiplegic Migraine Panel analyzes genes that are associated with familial hemiplegic migraine (FHM), alternating hemiplegia of childhood, and other conditions. [6] - How is a hemiplegic migraine diagnosed? · A genetic test. · A CT (computed tomography) scan. · An MRI (magnetic resonance imaging). · Lumbar puncture. [7] - Detects sequence variants in the CACNA1A, ATP1A2 and SCN1A genes in patients with migraine, migraine with aura, reversible hemiparesis, atypical migraine, and other conditions.

Treatment Options for Familial Hemiplegic Migraine Type 3 (FHM3)

Familial hemiplegic migraine type 3 (FHM3) is a rare subtype of migraine with aura, caused by variants in the SCN1A gene. While there are no specific treatments approved exclusively for FHM3, various medications have been used to manage symptoms and prevent attacks.

• Calcium Channel Blockers: Verapamil has been suggested as a potential preventive treatment for FHM3 (Source: [5]). Calcium channel blockers may help reduce the frequency and severity of migraine attacks.
• Other Migraine Prophylactics: Acetazolamide, another standard migraine prophylactic drug, may also be considered for FHM3 patients (Source: [6]).
• Blood Pressure Medications: Verapamil, a calcium channel blocker, has been used to treat an attack of hemiplegic migraine and may also be used preventively (Source: [5]).
• Triptans: Although triptans are generally avoided in hemiplegic migraine due to their vasoconstrictive properties, they have been used in some cases for acute treatment (Source: [9]).

It's essential to note that the efficacy and safety of these treatments for FHM3 specifically may vary. A healthcare professional should be consulted to determine the best course of treatment for an individual patient.

References:

[5] Nov 13, 2024 — Treating Hemiplegic Migraine · Blood pressure medications (verapamil, flunarizine): Oral verapamil may also be used preventively. [6] Most commonly, patients are treated with acetazolamide, another standard migraine prophylactic drug. [9] Familial hemiplegic migraine type 3 (1260327007) ... guidelines. PubMed.

The differential diagnosis of Familial Hemiplegic Migraine (FHM) type 3 involves considering other conditions that can cause transitory neurological signs and symptoms, such as:

• Other forms of migraine
• Cerebrovascular diseases
• Epilepsy with hemiparesis
• Infectious or inflammatory disease
• Tumors

According to [11], the differential diagnosis of FHM is broad, and these conditions should be considered in addition to other types of migraine. The most frequent differential diagnoses are summarized in Table 2.

FHM type 3 is caused by variants in the SCN1A gene, which can also cause other neurological disorders. Therefore, it's essential to consider these conditions when diagnosing FHM type 3.

In particular, [5] notes that if hemiplegia begins with migraine-like symptoms or with seizure, an etiological diagnosis should be considered, including conditions such as epilepsy with hemiparesis.

Additionally, [13] mentions that the diagnostic criteria for FHM require that at least one first- or second-degree relative has had attacks fulfilling the diagnostic criteria for hemiplegic migraine. This can help distinguish FHM from other conditions.

It's also worth noting that [12] suggests considering monogenic syndromes in which (atypical) migraine is part of the phenotype, especially if a patient suffers from a hereditary form of migraine with an autosomal dominant inheritance pattern.

Overall, the differential diagnosis of FHM type 3 requires careful consideration of various conditions and genetic mutations to ensure accurate diagnosis and treatment.