The broad clinical spectrum of hereditary neuropathy with liability to pressure palsy (HNPP)

Abstract

H ereditaty neuropathy with liability to pressure palsy (HNPP) is an autosomal dominant neuropathy encompassing a broad clinical phenotype spectrum, which usually makes its diagnosis difficult in an exclusive clinical basis. Recurrent sensory and motor neuropathy in a single nerve beginning in adolescence or young adulthood is characteristically seen. In most cases this recurrent clinical evolution is due to a PMP22 gene deletion. Mononeuropathies resulting from nerve pressure in entrapment points are the most common presentation, but an almost symmetric polyneuropathy can eventually be seen 1. Suggestive electrophysiological findings that draw attention for HNPP diagnosis are in consideration. DNA mutations tests are diagnostic, but not always available.Although it is an autosomal dominant condition, family history can be lacking in many cases, especially in Brazil, a country with a strong migration process and with different ethnics groups. In a recent comparison of causes of neuropathy in peripheral neuropathy reference centers in the United State of America and South-America (NA-SA project) we have observed a higher percentage of diagnoses of inherited neuropathies in the USA in comparison with Brazil: NA 292 (26.7%), SA 103 (10%) 2. In an American international reference center of inherited neuropathy an epidemiological study, including 787 Charcot-Marie-Tooth disease (CMT) patients, showed that only 67% received molecular diagnosis 3 . This result points that the diagnosis is performed mainly in clinical/ neurophysiological basis.This edition of Arquivos de Neuropsiquiatria includes an elegant study by Oliveira et al. 4reporting the clinical and neurophysiological features of HNPP due to the 17p11.2 deletion in 39 Brazilian patients, looking for its diagnostic characteristics. In this series, family history was present in 59% of cases, showing that clinical presentation, recurrence of signs and symptoms, and neurophysiological findings are strong elements for diagnostic suspicion. A progressive course is uncommon, but was reported in 20% of their HNPP patients 4. Older presentation of HNPP was seen in this series, in contrast with others. The first clinical manifestation was the classical painless muscle weakness with at least one episode of acute nerve paralysis (61,5% of cases). This painless acute or subacute mononeuropathy is the classical phenotype 1 . Pes cavus and nerve thickening, seen in CMT patients, was rare in Oliveira et al.4 HNPP series. Heterogeneity in clinical presentation and disease course is the rule in this neuropathy 1,5 . Atypical presentations of HNPP, as generalized weakness and cramps, chronic ulnar neuropathy, carpal tunnel syndrome, CMT phenotype, and Guillain-Barré-like syndrome, were included in the 74 patients series of Luigetti et al. 6 , comprising 56% of cases. In this Italian series the typical presentation of recurrent multiple mononeuropathies was not prevalent, occurring in only 44% of patients 6 . In a series of 12 children with confirmed PMP22 gene deletion, and...

Hereditary neuropathy with liability to pressure palsies: a case series report

“…Di delei da liai (85 %) at ve jø li ga pra si de da ûmios mo no neu ropa ti jos simp to mais [12]. Ta èiau PNSP ga li pa si reikð ti ir po li neu ro pa ti jai bû din gais kli ni ki niais po þy miais [1,2]. PNP bû din gais simp to mais taip pat skun dë si 1-asis, 4-asis, 6-asis, 7-asis mû sø ap ra ðy ti pa cien tai.…”

“…PNP bû din gais simp to mais taip pat skun dë si 1-asis, 4-asis, 6-asis, 7-asis mû sø ap ra ðy ti pa cien tai. Li gos simpto mai va ri juo ja nuo leng vo ju ti mø su tri ki mo iki ne gráþ tamo gru baus ga lû niø pa ra ly þiaus su at ro fi jo mis [1,11,13]. Pa si tai ko ir be simp to miø li gos at ve jø [2].…”

“…Taèiau iki ðiol dar në ra at lik ta pa kan ka mai ty ri mø, áro dan èiø, kad gy dy mas gliu ko kor to koi dais ga lë tø bû ti tai ko mas PNSP gy dy ti [11]. Taip pat svar bu tai, kad, ser gant PNSP, gal vi niai ner vai pa þei dþia mi daug re èiau nei uþ de gi mi niø PNP at ve ju [1,2,12].…”

“…

Pa vel di ma neu ro pa ti ja su po lin kiu á su spau di mo pa ra lyþius (PNSP) yra au to so mi niu do mi nan ti niu bû du pa vel dima re ta pe ri fe ri niø ner vø li ga, ku riai bû din ga pa si kar to janèios, epi zo di nës lo ka lios, daþ nai gráþ ta mos kom pre si nës pe ri fe ri niø ner vø neu ro pa ti jos, at si ran dan èios spon ta niðkai ar po mi ni ma lios ner vo trau mos. Kar tais, ypaè vy resnia me am þiu je, li gai pro gre suo jant nu sta to mi leng vos ar vi du ti nio sun ku mo po li neu ro pa ti jos (PNP) elek tro fi zio logi niai po þy miai [1]. 50 % pa cien tø vi sið kai pa sveiks ta po ûmaus epi zo do [2].

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