Peripheral nerve biopsy study in 19 cases with 17p11.2 deletion (HNPP)

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Abstract from J Neuropathol Exp Neurol. 2004 Nov;63(11):1167-72.

Peripheral nerve biopsy study in 19 cases with 17p11.2 deletion.

Vital A, Vital C, Latour P, Ferrer X, Rouanet-Lariviere M,

Brechenmacher C, Lagueny A.

Department of Neuropathology, Laboratoire de Neurobiologie des

Affections de la Myeline, Victor Segalen-Bordeaux 2 University,

Bordeaux, France. anne.vital@...

In most cases of hereditary neuropathy with liability to pressure

palsy (HNPP) the diagnosis is now assessed by molecular detection of

17p11.2 deletion. However, the family history may be missing and the

clinical presentation is not always informative. In such cases, a

peripheral nerve biopsy showing the characteristic focal myelin

sheath thickening ( " tomaculae " ) may be helpful. We present a

retrospective study of peripheral nerve biopsies performed in 19

patients suffering from either a mononeuropathy or a generalized

sensory-motor polyneuropathy, and for whom the finding of tomaculae

led to a search for 17p11.2 deletion, which was confirmed

secondarily. Tomaculae and other coexisting neuropathological lesions

such as uncompacted myelin, " onion bulb " formations, and axonal

degeneration are described and discussed in the view of previously

reported data. It appears that demyelinating lesions with tomaculae

are strongly suggestive of HNPP but are not specific as they may be

observed in other conditions. Moreover, these features may be

overlooked if axonal degeneration is marked.