Casandra

Casandra Test Code BA35615Version 1 (DRAFT)

Performing Lab

Lab Baylor GeneticsLab Test ID 8467CPT Codes 88230, 88271, 88273, 88274, 88291

FISH Analysis - Hereditary Neuropathy with Liability to Pressure Palsies

Clinical Use

Use

FISH Analysis – Hereditary Neuropathy with Liability to Pressure Palsies is designed to detect deletions in the PMP22 gene associated with hereditary neuropathy with liability to pressure palsies (HNPP). PMP22 deletions account for approximately 80% of HNPP diagnoses. This test is indicated for patients with clinical or suspected diagnosis of HNPP, those who have not undergone previous PMP22 del/dup testing, and symptomatic patients with a family history of HNPP. While this test is critical, it has limitations, as patients may present with other disease-causing variants not detectable through this assay. Screening by Chromosome Microarray Analysis is recommended for comprehensive insights.

Special Instructions

This assay requires specimens to be drawn in a Sodium Heparin (green-top) tube. For optimal analysis, specimens sent for testing should be shipped at room temperature via overnight courier. The transportation conditions are critical, necessitating delivery to the laboratory within 48 hours post-collection. Patients must refrain from any heating or freezing of specimens to maintain integrity for accurate test results. Coordination with testing facilities may be essential for proper processing.

Limitations

The FISH assay only determines gains or losses of the PMP22 gene. A normal result does not eliminate the possibility of other structural rearrangements or variants present in other genes associated with HNPP. Therefore, relying solely on this test can lead to undetected conditions that may affect patient management.

Test Details