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Peripheral nerve biopsy study in 19 cases with 17p11.2 deletion
Anne Vital1, Claude Vital, Philippe Latour
1Department of Neuropathology, Laboratoire de Neurobiologie des Affections de la Myéline, Victor Segalen-Bordeaux 2 University, Bordeaux, France. anne.vital@neuropath.u-bordeaux2.fr
Journal of Neuropathology and Experimental Neurology
|December 8, 2004
Summary
Peripheral nerve biopsy findings of focal myelin sheath thickening (tomaculae) can aid in diagnosing hereditary neuropathy with liability to pressure palsy (HNPP) when genetic testing is inconclusive. This study highlights tomaculae as suggestive, though not exclusive, indicators of HNPP.
Area of Science:
- Neurology
- Pathology
- Genetics
Background:
- Hereditary neuropathy with liability to pressure palsy (HNPP) is typically diagnosed via molecular detection of the 17p11.2 deletion.
- Clinical presentation and family history in HNPP can be ambiguous, necessitating alternative diagnostic approaches.
Purpose of the Study:
- To evaluate the diagnostic utility of peripheral nerve biopsy findings, specifically tomaculae, in identifying HNPP.
- To correlate histopathological findings with genetic confirmation of 17p11.2 deletion in patients with suspected HNPP.
Main Methods:
- Retrospective analysis of peripheral nerve biopsies from 19 patients with mononeuropathy or sensory-motor polyneuropathy.
- Histopathological examination for tomaculae, uncompacted myelin, onion bulb formations, and axonal degeneration.
- Subsequent genetic testing for 17p11.2 deletion in patients with suggestive biopsy findings.
Main Results:
- Peripheral nerve biopsies revealed tomaculae in all 19 patients, leading to the identification of the 17p11.2 deletion.
- Coexisting neuropathological features included uncompacted myelin, onion bulb formations, and axonal degeneration.
- Tomaculae were strongly suggestive of HNPP but also observed in other neuropathies, and could be obscured by significant axonal degeneration.
Conclusions:
- Peripheral nerve biopsy findings, particularly tomaculae, are valuable in diagnosing HNPP when genetic testing is inconclusive or unavailable.
- While tomaculae are characteristic of HNPP, their presence alone is not pathognomonic and requires correlation with clinical and genetic data.
- Careful histopathological assessment is crucial, as other lesions may coexist and potentially mask the characteristic findings of HNPP.