A new study which appears to show that two parents both with HNPP, one with the common deletion, and one with a partial deletion of the PMP22 gene, have a child who inherited both mutations and developed a severe form of CMT, Dejerine Sotas Disease (DSD).
Another point of interest is that toward the end of the abstract it is mentioned that the child developed a severe form of GERD, which hasn’t been notice in CMT or DSD before.
It’s a shame Doctors don’t take more notice of what their HNPP patients tell them. Personally I don’t have GERD at all, but the anecdotal reports of GERD on HNPP support groups are numerous, and can often involve other swallowing problems as well. Mostly, I would imagine, these symptoms are dismissed as not being HNPP related, which is possible, although this study should prompt further investigations…
Compound heterozygous deletions of PMP22 causing severe Charcot-Marie-Tooth disease of the Dejerine-Sottas disease phenotype.
F. Clarke Fraser Clinical Genetics Unit, Division of Medical Genetics, McGill University Health Centre/Montreal Children’s Hospital, Montreal, Quebec, Canada.
Dejerine-Sottas disease (DSD) is a particular phenotype of the Charcot-Marie-Tooth (CMT) disease spectrum that is genetically heterogeneous. It represents a severe form of hypertrophic axonal and demyelinating neuropathy. Although it is predominantly inherited as an autosomal recessive condition, autosomal dominant inheritance has also been described. To date, the autosomal recessive forms of DSD are classified into several CMT type 4 (CMT4) subclasses based on allelic heterogeneity. We present a 7-year-old boy with a severe form of CMT disease consistent with the autosomal recessive phenotype of DSD. He was found to be a compound heterozygote for mutations in the PMP22 gene resulting in homozygous deletion of exons 2 and 3. The maternally inherited allele was the typical 1.5 Mb deletion involving PMP22 seen with hereditary neuropathy with liability to pressure palsy (HNPP). The paternally inherited allele was a deletion of exons 2 and 3. Both parents presented with a typical clinical picture of HNPP. To our knowledge, this is the first patient reported with large deletions involving both PMP22 alleles. Our patient has also developed severe gastroesophageal reflux disease (GERD), a clinical feature not previously reported with CMT or DSD. The correlation of the phenotype and the molecular defects observed in this patient may set a new subcategory in the classification of DSD. (c) 2008 Wiley-Liss, Inc.
PMID: 18698610 [PubMed – as supplied by publisher]