J Clin Neurol.  2007 Jun;3(2):101-104. 10.3988/jcn.2007.3.2.101.

A Family Harboring CMT1A Duplication and HNPP Deletion

• Lee JH
• Kang HJ
• Song H
• Hwang SJ
• Cho SY
• Kim SB
• Kim J
• Chung KW
• Choi BO

• KMID: 1851021
• DOI: http://doi.org/10.3988/jcn.2007.3.2.101

Abstract

Charcot-Marie-Tooth disease type 1A (CMT1A) is associated with duplication of chromosome 17p11.2-p12, whereas hereditary neuropathy with liability to pressure palsies (HNPP), which is an autosomal dominant neuropathy showing characteristics of recurrent pressure palsies, is associated with 17p11.2-p12 deletion. An altered gene dosage of PMP22 is believed to the main cause underlying the CMT1A and HNPP phenotypes. Although CMT1A and HNPP are associated with the same locus, there has been no report of these two mutations within a single family. We report a rare family harboring CMT1A duplication and HNPP deletion.

Keyword

Charcot-Marie-Tooth disease; HNPP; PMP22

MeSH Terms

Charcot-Marie-Tooth Disease
Gene Dosage
Humans
Paralysis
Phenotype

Figure

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  Figure 1 Pedigree of the family with peripheral neuropathy. The proband (III-1) was identified with a de novo CMT1A duplication of paternal origin, whereas her mother (II-4) carried an HNPP deletion (open symbols: unaffected; black symbols: HNPP; gray symbol: CMT1A).

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  Figure 2 Conduction in the median nerve showing the uniform shape and amplitudes of the compound muscle action potential for stimulation at the wrist, elbow, and above the elbow. The different gene dosages of the same region (1.5 for CMT1A and 0.5 for HNPP compared with control) resulted in different electrophysiological features in the family. (A) Patient 1 (III-1) with 17p11.2-p12 duplication, and (B) patient 2 (II-4) with 17p11.2-p12 deletion.

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