Hereditary Neuropathy with Liability to Pressure Palsy: An Investigation in a Rare and Large Chinese Family

Abstract

Background: Hereditary neuropathy with liability to pressure palsy (HNPP), mainly associated with the peripheral myelin protein 22 (PMP22) gene, is generally an autosomal-dominant inherited peripheral neuropathy. The present large family including four generations provides an exciting opportunity to gain important insights into HNPP in China. Patients and Methods: A large 43-member family with ten members suspected to be affected by HNPP was studied. Neurologic examinations, electrophysiological and neuropathological studies and molecular genetic testing were used for these kindred. Results: Clinically, the proband had limb hyposthenia and atrophy, and his mother showed declined tendon reflexes in the right lower limb. Electrophysiologically, sensory and motor nerve conduction velocities were generalized reduced. Sural nerve biopsy for the proband showed focal thickesning of the myelin sheaths. Furthermore, real-time quantitative PCR demonstrated that the PMP22 gene has a higher Ct value than reference gene in all suspected patients. Conclusions: These results indicated that the family is indeed a rare and large pedigree of HNPP caused by the deletion of PMP22 gene. Given that the suspected patient in the fourth generation is absent, this family is still worthy of further follow-up study.

DTI Study of Cerebral Normal-Appearing White Matter in Hereditary Neuropathy With Liability to Pressure Palsies (HNPP)

“…22 , 23 In addition, teased nerve fibers of sural nerve biopsies from HNPP patients demonstrate the evidence of axonal compression and deformation. 24 Demyelination, a lower axonal packing density, decreased axonal number, and intravoxel orientation difference caused by axonal compression and deformation will contribute to the relatively decreased FA values. 25 The PMP22 gene deletion has been considered to be the cause of HNPP, which is also observed in CNS.…”

Reply

“…We thank Delacour et al [1] for their comments on our paper entitled ‘Hereditary neuropathy with liability to pressure palsy: an investigation in a rare and large Chinese family' [2]. We agree that a simple standard electrophysiological examination is sufficient to identify altered PMP22 gene carriers before the onset of the first episode of hereditary neuropathy with liability to pressure palsies (HNPP).…”

Comments on ‘Hereditary Neuropathy with Liability to Pressure Palsy: An Investigation in a Rare and Large Chinese Family'

“…We read with interest the article by He et al [1] about the investigation of hereditary neuropathy with liability to pressure palsies (HNPP) in a large Chinese family. The authors described a 43-member family that included 10 suspected patients among 4 generations.…”