MRI use in HSMN - from Italy

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(Dejerine-Sottas is also known as CMT Type 3)

1: J Neurol 2002 Sep;249(9):1298-302

Dejerine-Sottas neuropathy with multiple nerve roots enlargement and

hypomyelination associated with a missense mutation of the transmembrane

domain of MPZ/P0.

Simonati A, Fabrizi GM, Taioli F, Polo A, Cerini R, Rizzuto N.

Department of Neurological and Visual Science, Section of Clinical

Neurology, Policlinico GB Rossi, P.le LA Scuro 1, 37134 Verona, Italy.

alessandro.simonati@...

In a patient affected with a slowly progressive, severe form of

Dejerine-Sottas

syndrome, symmetric enlargement of cranial nerves and focal hypertrophy

of cervical and caudal roots were detected following MRI.

Neuropathological features of the sural nerve disclosed a dramatic loss

of myelinated fibres, with skewed-to-the-left, unimodal distribution of

the few residual fibres, consistent with the diagnosis of congenital

hypomyelination neuropathy. Genetic analysis revealed this condition to

be associated with a heterozygous G to A transition at codon 167 in the

exon 4 of the MPZ/P0 gene causing a Gly138Arg substitution in the

transmembrane domain of the mature MPZ/P0 protein. Focal enlargement of

the nerve trunks in demyelinating, hereditary motor and sensory

neuropathies (HMSN) was previously reported in both asymptomatic

and symptomatic cases with root compression, but peculiar to this case

is the

diffuse involvement of both cranial and spinal nerves.

We believe that the relevance of nerve trunk hypertrophy in HMSN is

probably underevaluated: therefore MRI investigation of the head and

spine should be included in the diagnostic study of selected HMSN

patients. Molecular analysis of peripheral

myelin genes will help to rule out misdiagnosed cases.