Heat shock protein 27 R127W mutation: evidence of a continuum between axonal Charcot-Marie-Tooth and distal hereditary motor neuropathy.
BACKGROUND
Heat shock protein 27 (HSP27) mutations have been reported to cause both Charcot-Marie-Tooth disease (CMT) type 2F and distal hereditary motor neuropathy (dHMN) although never previously in a single family.


OBJECTIVE
To analyse clinical and electrophysiological findings obtained in a single large Sardinian family bearing the HSP27 R127W mutation.


METHODS
Twenty-one members of a five generation Sardinian family have been studied, including thirteen members affected by peroneal muscular atrophy and proved heterozygous for the known HSP27 R127W mutation. Twelve patients and eight unaffected relatives were subjected to clinical examination. A standardised electrophysiological study was performed in eleven patients and six unaffected relatives.


RESULTS
Mean age at onset (+/-SD) was 31.2+/-7.2 years. Mean age at investigation was 45.2+/-12.9 years and mean disease duration at the time of investigation was 14+/-12.9 years. According to current criteria for CMT2 and dHMN, of the 10 patients who had undergone both clinical and neurophysiological examination, five were diagnosed as CMT2, two as dHMN and a further two patients were labelled as an intermediate type. Finally, due to the presence of spastic paraplegia, the index patient did not meet established criteria for the diagnosis of CMT or dHMN.


CONCLUSIONS
Findings obtained in the present study, broadening the spectrum of clinical manifestations of disorders associated with HSP27 mutations, support the hypothesis of a continuum between CMT2 and dHMN forms and suggest a possible common spectrum between these entities and several forms of CMT plus pyramidal features (HMSN V), providing important implications for molecular genetic testing.
Solla
Paolo
P
Centro Sclerosi Multipla, Ospedale Binaghi, University of Cagliari, Cagliari, Italy. paosol29@yahoo.it
Vannelli
Alessandro
A
Bolino
Alessandra
A
Marrosu
Giovanni
G
Coviello
Silvia
S
Murru
Maria Rita
MR
Tranquilli
Stefania
S
Corongiu
Daniela
D
Benedetti
Sara
S
Marrosu
Maria Giovanna
MG
D000328:Adult; D002607:Charcot-Marie-Tooth Disease / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D004594:Electrophysiology / Q000379:methods; D005260:Female; D020022:Genetic Predisposition to Disease; D055551:HSP27 Heat-Shock Proteins / Q000235:genetics*; D015417:Hereditary Sensory and Motor Neuropathy / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000502:physiology*; D010375:Pedigree; D010641:Phenotype; D015419:Spastic Paraplegia, Hereditary / Q000235:genetics
D055551:HSP27 Heat-Shock Proteins