PMP22 Deletion/Duplication

Duplications of PMP22 result in Charcot-Marie-Tooth type 1A (CMT1A), which is a condition characterized by distal muscle weakness and atrophy, sensory loss, and slow nerve conduction velocity. Age of onset is variable. Duplications of PMP22 account for the majority of (70-80%) cases of CMT. This condition is inherited in an autosomal dominant manner. This test does not test other genes that are associated with CMT. If this diagnosis is suspected and a duplication is not found, there are other laboratories that perform testing on additional genes associated with CMT.

Deletions of PMP22 result in Hereditary Neuropathy with Liability to Pressure Palsies (HNPP), which is a condition characterized by repeated focal neuropathies such as carpal tunnel syndrome and peroneal palsy with foot drop. Symptoms usually begin sometime during the second and third decade of life. 80% of cases are due to a deletion of PMP22, while the remaining 20% are due to a sequence variant. This condition is inherited in an autosomal dominant manner. This MLPA test detects deletions/duplications of PMP22 but no sequence variants.

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Test Code
C0998

Turn Around Time
2-3 weeks

Billing

CPT Code
81324×1

Ordering Guidance

The majority of cases are due to a duplication of PMP22. Typically testing starts with duplication analysis of PMP22 followed by testing of the other associated genes if PMP22 duplication is negative.

If there are questions regarding this test, please contact Client Services at 617-553-5880 or clientservices@claritasgenomics.com

Details

Genes Covered
PMP22

Methods
MLPA