CHARCOT-MARIE-TOOTH DISEASE (CMT) & HEREDITARY NEUROPATHY WITH LIABILITY TO PRESSURE PALSIES (HNPP)

Background

The hereditary neuropathies are a clinically and genetically heterogeneous group of disorders characterised clinically by distal muscle wasting and weakness, distal sensory loss, reduced tendon reflexes, hypoflexia, variable amount of foot deformity and neurophysiological changes. There are in excess of 30 genes associated with inherited peripheral neuropathies, and 75% of the causative genes are still unknown. CMT type 1 (CMT1 OMIM 118220) is the most common clinical form and it is usually inherited as an autosomal dominant condition. Duplication of the PMP22 gene region may be found in up to 70% of inherited and 90% of sporadic cases of CMT type 1A (CMT1A), the most common subtype of CMT1. HNPP (also known as tomaculous neuropathy OMIM 162500) is genetically related to CMT1A. Approximately 84% of HNPP patients have a deletion of the PMP22 gene region.
 

 Testing at WRGL

MLPA analysis is performed using a commercially available kit from MRC Holland (www.mrc-holland.com) followed by analysis on a 3500XL Genetic Analyser. This kit can detect dosage changes (deletions/duplications) of the PMP22, MPZ and GJB1 genes; associated with clinical CMT1A or HNPP, CMT1B and X-linked CMT, respectively. Data is analysed using GeneMarker software (www.softgenetics.com). Results are compared with positive and negative controls.
 

Cost, Sample Requirements & Turnaround Times