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Brainstem dysfunction in variegate porphyria.
Gonzalo Barraza1, Tereza Serranova, Carmen Herrero
1Neurology Department, EMG and Motor Control Unit, Hospital Clínic, Villarroel 170, Barcelona 08036, Spain.
Muscle & Nerve
|August 22, 2012
Summary
Variegate porphyria (VP) can affect brainstem function, causing abnormal reflexes in patients with a history of porphyric crises. Asymptomatic carriers did not show these neurological deficits.
Area of Science:
- Neurology
- Metabolic Disorders
- Neurophysiology
Background:
- Variegate porphyria (VP) is a rare metabolic disorder.
- VP can manifest as acute motor neuropathy.
- Brainstem and cranial nerve involvement in VP is poorly understood.
Purpose of the Study:
- To investigate brainstem reflex abnormalities in Variegate porphyria.
- To compare findings between symptomatic and asymptomatic VP mutation carriers.
Main Methods:
- Examination of brainstem reflexes.
- Study conducted on symptomatic and asymptomatic VP mutation carriers from a single family.
Main Results:
- Patients with a history of porphyric crises showed absent late responses in the blink reflex.
- Reduced inhibition was observed in the masseter inhibitory reflex.
- Asymptomatic carriers exhibited normal brainstem reflex responses.
Conclusions:
- Findings suggest a central lower pons-upper medulla disorder in VP patients with porphyric crises.
- Hypothesized causes include neurotoxic porphyrin precursors and hyponatremia-induced osmolarity changes.
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