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GTR Home > Tests > Charcot-Marie-Tooth disease, type 4A, 214400, Autosomal recessive; CMT4A (Charcot-Marie-Tooth disease type 4A) (MLPA)


This is a clinical test intended for Help: Diagnosis

Clinical summary


Imported from GeneReviews

GDAP1-related hereditary motor and sensory neuropathy (GDAP1-HMSN) is a peripheral neuropathy (also known as a subtype of Charcot-Marie-Tooth disease) that typically affects the lower extremities earlier and more severely than the upper extremities. As the neuropathy progresses, the distal upper extremities also become severely affected. Proximal muscles can also become weak. Age at onset ranges from infancy to early childhood. In most cases, disease progression causes disabilities within the first or second decade of life. At the end of the second decade, most individuals are wheelchair bound. Disease progression varies considerably even within the same family. The neuropathy can be either of the demyelinating type with reduced nerve conduction velocities or the axonal type with normal nerve conduction velocities. Vocal cord paresis is common. Intelligence is normal. Life expectancy is usually normal, but on occasion may be reduced because of secondary complications.

Clinical features


Imported from Human Phenotype Ontology (HPO)

  • Areflexia
  • Distal muscle weakness
  • Kyphoscoliosis
  • Hyporeflexia
  • Hammertoe
  • Hypertrophic nerve changes
  • Axonal degeneration
  • Distal sensory impairment
  • Onion bulb formation
  • Distal amyotrophy
  • Decreased sensory nerve conduction velocity
  • Motor delay
  • Decreased number of peripheral myelinated nerve fibers
  • Decreased motor nerve conduction velocity
  • Inability to walk by childhood/adolescence
  • Basal lamina onion bulb formation
  • Segmental peripheral demyelination
  • CNS hypomyelination
  • Ulnar claw
  • Peripheral axonal degeneration
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Conditions tested

Target population


Charcot-Marie-Tooth disease, type 4A, 214400, Autosomal recessive; CMT4A (diagnosis/ clinical suspition/ etiology investigation/ classification)


Not provided

Clinical validity


Not provided

Clinical utility


Not provided

Practice guidelines

  • EuroGenetest, 2010
    Clinical utility gene card for: HMSN/HNPP HMSN types 1, 2, 3, 6 (CMT1,2,4, DSN, CHN, GAN, CCFDN, HNA); HNPP

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