From the Guidelines
Abetalipoproteinemia leads to peripheral neuropathy primarily due to vitamin E deficiency, not the absence of LDL-C.
Key Factors
- Vitamin E deficiency is the main cause of neurological manifestations, including peripheral neuropathy, in abetalipoproteinemia patients 1.
- Lipid soluble vitamins (A, D, E, K) deficiency is a characteristic of abetalipoproteinemia, resulting from the inability to fully assemble and secrete lipoproteins 1.
- Demyelination associated with vitamin E deficiency leads to neurological presentations, including peripheral neuropathy 1.
- Lifelong supplementation with high-dose vitamin E appears to halt further neurological degeneration in abetalipoproteinemia patients 1.
Clinical Implications
- Abetalipoproteinemia patients are at risk of developing peripheral neuropathy due to vitamin E deficiency, which can be managed with high-dose vitamin E supplementation 1.
- Vitamin E supplementation (200 mg/day) can improve neurological symptoms, including peripheral neuropathy, in patients with fat malabsorption and vitamin E deficiency 1.
- Early diagnosis and treatment of vitamin E deficiency are crucial to prevent long-term neurological damage in abetalipoproteinemia patients.
From the Research
Pathophysiology of Abetalipoproteinemia
Abetalipoproteinemia is a genetic disorder characterized by the inability to fully assemble and secrete lipoproteins, leading to malabsorption of fat and fat-soluble vitamins [(2,3,4,5)]. This deficiency affects all classes of plasma lipoproteins, resulting in severe hypolipidemia 2.
Clinical Features
Patients with abetalipoproteinemia typically manifest steatorrhea, vomiting, and failure to thrive in infancy 3. The deficiency of fat-soluble vitamins progressively develops into a variety of symptoms later in life, including:
- Hematological symptoms (acanthocytosis, anemia, bleeding tendency, etc.) [(3,4,5)]
- Neuromuscular symptoms (spinocerebellar ataxia, peripheral neuropathy, myopathy, etc.) [(2,3,4,5)]
- Ophthalmological symptoms (e.g., retinitis pigmentosa) [(3,4,5)]
Peripheral Neuropathy
The exact mechanism of peripheral neuropathy in abetalipoproteinemia is not fully understood, but it is thought to be related to the deficiency of fat-soluble vitamins, particularly vitamin E [(2,6)]. EMG findings have shown axonal neuropathy, and somatosensory evoked potentials have demonstrated dorsal column dysfunction 2. The therapeutic role of vitamin E supplementation has been discussed, and high-dose vitamin supplementation is the mainstay for treatment [(2,3,4,5)].
Treatment and Management
Treatment of abetalipoproteinemia includes adherence to a low-fat diet and supplementation with essential fatty acids and high oral doses of fat-soluble vitamins [(3,4,5)]. Early diagnosis and strict adherence to treatment can recover normal neurological function and halt disease progression 4. Novel therapeutic modalities that improve quality of life and prognosis are awaited 3.