After recently commenting that there are few if any long term studies on patients with HNPP, along comes one, if they’re like buses then chances are we’ll have a spate of them.
Unfortunately this is an abstract only, the full article available for a fee. (link in title)
Clinical, neurophysiological and pathological findings of HNPP patients with 17p12 deletion: A single-centre experience.
- 1Dept. of Geriatrics, Neurosciences & Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy. Electronic address: firstname.lastname@example.org.
- 2Dept. of Geriatrics, Neurosciences & Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
- 3Institute of Medical Genetics, Catholic University of the Sacred Heart, Rome, Italy.
- 4Dept. of Geriatrics, Neurosciences & Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy; IRCCS, S. Raffaele-Pisana, Rome, Italy; Casa di Cura, S. Raffaele Cassino, Cassino, Italy.
Classic clinical manifestations of HNPP are characterized by recurrent painless mononeuropathies, but a minority of patients present with an atypical clinical pattern, including CMT-like neuropathy, acute or chronic inflammatory demyelinating neuropathy-like polyneuropathy, and carpal tunnel syndrome. Electrophysiological examination plays a central role in the diagnosis of HNPP, disclosing a non-uniform conduction slowing, more pronounced at entrapment sites.
PATIENTS AND METHODS:
We report clinical, electrophysiological and pathological findings from 73 patients with HNPP, coming from 53 unrelated families, followed at our Institute of Neurology over a 20-year period.
Typical presentation with recurrent multiple mononeuropathies was observed in 28/64 (44%) patients. In the remaining 36/64 (56%), we observed an atypical clinical presentation, characterized by generalized weakness and cramps, chronic ulnar neuropathy, carpal tunnel syndrome, chronic sensory polyneuropathy, Guillain-Barrè-like presentation, and CMT-like presentation. Nine patients were asymptomatic for neuropathic symptoms. Nerve conduction studies showed in all cases a sensori-motor demyelinating polyneuropathy with conduction abnormalities preferentially localized at common entrapment sites. When performed, sural nerve biopsy disclosed the focal thickening of the myelin sheath in all patients.
About half of the patients with HNPP from our cohort showed an atypical clinical presentation. Neurophysiological examination represents the main tool for a proper diagnosis.
The thing that grabs my attention from this study is the disparity between the background, which seems to keep to the standard line that HNPP mostly causes ‘recurrent painless mononeuropathies’, and that atypical presentations are not the norm. And, the results and conclusion which paint a different picture, where recurrent painless mononeuropathies are in the minority, 44%, whilst the previously thought of ‘atypical’ presentations, as a whole, have a higher incidence of 56%.
These figures appear to be more consistent with the reports found on patient self-help forums and groups. I have heard of many neurologists who have dismissed these ‘atypical’ presentations, and reports of such, as rare and anecdotal. Well not so any more. Still this is but one long-term study, and as is often the case, studies tend to find slightly different results, and it is only when the results of many such studies can be compared that true patterns emerge. But it’s a step in the right direction.