A new familial nodo-paranodopathy in American Staffordshire Terriers

Introduction:

A new early-onset polyneuropathy has been increasingly recognized in related American Staffordshire Terriers across Europe. Clinical signs are stereotypic and comprise muscle atrophy, ataxia, decreased spinal reflexes, cutaneous hypoalgesia and laryngeal paralysis. Herein we describe the histopathologic features of this new familial polyneuropathy.

Materials and methods:

Nerve biopsies from 11 symptomatic American Staffordshire Terriers were submitted for diagnostic investigation. Nerve fibre teasing and semithin sections were investigated on light microscopy applying general algorithms for evaluation of nerve biopsies. Ultrathin sections were subsequently analysed by electron microscopy.

Results:

All submitted biopsies featured loss of myelinated nerve fibres, paranodal retraction with dysmorphic paranodes and tomacula formation. Half of the patients further displayed very mild lymphohistiocytic infiltrates in the proximity of the paranodes.

Discussion:

Histopathologic features are consistent with a degenerative, distally accentuated nodo-paranodopathy. Some of the cases further exhibited inflammatory changes similar to immune-mediated neuropathies type 2, which might be targeted therapeutically and thus may serve as predictive parameter for patient care.