Nerve and muscle impairment defined

Chinese study links SPG6 mutation to HSP expression

Mutations in the NIPA1 gene cause autosomal dominant hereditary spastic paraplegia (ADHSP). To date, little is known about the relationship between genotype-phenotype correlation. In order to examine the gene mutation associated with the genotype-phenotype of Chinese kindred with ADHSP, linkage analysis and mutation detection were performed.

For affected family members, clinical analysis, electrophysiological examination and MRI of the brain and spinal cord were also performed. Every affected patient had a c316 (G106R) mutation in the NIPA1 gene.

Neurophysiological examination revealed:

  • Decreased amplitude of compound muscle action potentials (CMAP) from the tibial and peroneal motor nerves in most patients.
  • Sensory nerve action potential (SNAP) from the tibialis nerve was not elicited in most patients.
  • Central motor conduction time (CMCT) to the abductor pollicis brevis muscle (APB), first metatarsal interosseus muscle (FMI) and anterior tibial muscle (AT) were either absent or clearly prolonged in all patients.
  • Spinal cord MRI showed different levels of atrophy in every affected individual. These lesions present an increased spot or patch signal on transverse axis T2WI and an intense signal of continual longitudinal strip on the anteroposterior axis.

Our study supports that mutations in the NIPA1 gene cause ADHSP and further demonstrates genotype-phenotype correlations in SPG6.

SOURCE: J Neurol Sci. 2007 Oct 8

Clinical and genetic study of SPG6 mutation in a Chinese family with hereditary spastic paraplegia.

Liu SG, Zhao JJ, Zhuang MY, Li FF, Zhang QJ, Huang SZ, Che FY, Lu DG, Liu SE, Teng JJ, Ma X.

Graduate School of Peking Union Medical College, Beijing, China; National Research Institute for Family Planning, Beijing, China.

PMID: 17928003 [PubMed – as supplied by publisher]