Charcot Marie Tooth 1A (CMT1A) and HNPP

Charcot-Marie-Tooth disease (CMT) is a group of neurodegenerative disorders (CMT1, CMT2, CMT4 and CMTX), each one divided into further subgroups. Amongst them, CMT1A is the classic form of the disorder, accountable for ~75/80% of all cases of CMT1, and is caused by mutations of the PMP22 gene. It is inherited in an autosomal dominant manner and typical symptoms, that manifest progressively, include muscle weakness and atrophy, along with loss of touch sensation. The CMT1A form is caused in >99% of cases by duplication of the PMP22 gene, whilst deletion of the same gene also cause a neuropathy known as Hereditary Neuropathy with liability to Pressure Palsies (HNPP).

NOTE: Our laboratory participates with great success in the external quality assessment scheme organized by the European Molecular Genetics Quality Network (EMQN), which is periodically applied for Charcot Marie Tooth 1A.

The test includes full analysis for the detection of deletions/duplications of the PMP22 gene, using MLPA, thus being able to diagnose reliably both CMT1A and HNPP. For all prenatal molecular genetic testing, we perform analysis of polymorphic STR markers from a maternal blood sample and the fetal sample, in order to exclude any possible maternal cell contamination. Thus, for prenatal diagnosis, 1-2ml of a maternal blood sample should always accompany the fetal sample (amniotic fluid or CVS).