Invitae Cystinosis Test

Casandra

Casandra Test Code IN06172Version 1 (DRAFT)

Performing Lab

Lab Invitae CorporationLab Test ID 06172

Invitae Cystinosis Test

Clinical Use

Use

The Invitae Cystinosis Test analyzes the CTNS gene associated with cystinosis, characterized by cystine crystal accumulation in tissues. It assists in diagnosing suspected cystinosis, enabling accurate risk assessment and determining carrier status for at-risk relatives. The test is important for identifying disease-causing variants, allowing for potential early intervention and management of the disorder. Treatment options such as cystine depletion therapies can prevent systemic complications, improving long-term survival. For individuals with early treatment, survival into the sixth decade is possible.

Special Instructions

The preferred specimen for this test is 3mL of whole blood collected in a purple-top EDTA tube (K2EDTA or K3EDTA). Alternate specimen types such as saliva, buccal swab, and gDNA are also accepted. This test is performed by Invitae, a CAP-accredited and CLIA-certified clinical diagnostic laboratory, using full-gene sequencing and deletion/duplication analysis through NGS technology. Specimens should be collected following the provided instructions, and a specimen collection kit can be requested from the provider.

Limitations

This test covers clinically important regions of the CTNS gene, focusing on coding exons and adjacent intronic sequences. While it provides high analytical sensitivity and specificity for SNVs, insertions, and deletions, it may not fully detect structural rearrangements, variants in non-coding regions, or single-exon copy number events in rare situations. Validation studies show >99% sensitivity and specificity for certain small variants, but larger indels and copy number variations may have marginally reduced sensitivity. Variants with complex sequence architecture and non-constitutional DNA sources could limit analysis.

Test Details

New York Approved