Objective: To report unusual electrophysiologic data in a patient with Tangier disease in an effort to better understand the pathophysiologic features of the peripheral nerve lesions in this disease.
Design: Case report.
Patient: A 15-year-old girl had subacute onset of asymmetric neuropathy with persistent conduction block, resembling Lewis-Sumner syndrome.
Main outcome measures: Electrophysiologic data in Tangier disease.
Results: After initially unsuccessful treatment with intravenously administered immunoglobulins, the finding of an abnormal lipid profile led to the diagnosis of Tangier disease due to the R587W mutation in the adenotriphosphate-binding cassette transporter-1 gene (ABCA1) (OMIM 9q22-q31).
Conclusions: Conduction block, which is the electrophysiologic hallmark of focal demyelination, can be present in Tangier disease. It could be induced by focal nerve ischemia or by preferential lipid deposition in the paranodal regions of myelinated Schwann cells. The presence of a conduction block in Tangier disease may lead to a misdiagnosis of dysimmune neuropathy.