A family with a novel frameshift mutation in the PMP22 gene (c.433_434insC) caus

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Neuromuscul Disord. 2005 Jun 12; (NOTE: HNPP is the genetic opposite

of CMT)

A family with a novel frameshift mutation in the PMP22 gene

(c.433_434insC) causing a phenotype of hereditary neuropathy with

liability to pressure palsies.

Zephir H, Stojkovic T, Latour P, Hurtevent JF, Blankaert F, Vermersch

P.

Clinique Neurologique, CHRU de Lille, 59047 Lille Cedex, France.

Hereditary neuropathy with liability to pressure palsies is usually

due to PMP22 deletion. Point mutations of PMP22 causing an hereditary

neuropathy with liability to pressure palsies phenotype are rare. We

describe a clinical and electrodiagnostic phenotype of hereditary

neuropathy with liability to pressure palsies in a 21-year-old woman,

which led to our detecting a novel frameshift mutation of PMP22. This

mutation was also found in her mother and brother and corresponded to

an insertion of one cytidine between nucleotides 433 and 434 in the

last coding exon (c.433_434insC). The mutated PMP22 protein lacks the

last 15 amino acids and has a modified C terminus lengthened to 221

residues instead of 160 (Leu145fsX222). The mother and the proband

had a clinical and electrophysiological hereditary neuropathy with

liability to pressure palsies phenotype. The brother was

asymptomatic, but the results of electrodiagnostic tests were

suggestive of hereditary neuropathy with liability to pressure

palsies. This observation of a new mutation mostly leading to a PMP22

haploinsufficiency provides further evidence of the diversity of

phenotypes associated with frameshift PMP22 mutations.