Ordering Recommendation

Confirm a clinical diagnosis of familial transthyretin (TTR) amyloidosis, familial euthyroid hyperthyroxinemia, or senile systemic amyloidosis.

Mnemonic

TTR FGS

Methodology

Polymerase Chain Reaction/Sequencing

Performed

Sun-Sat

Reported

Within 14 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation
Collect

Lavender (EDTA), Pink (K2 EDTA).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval

Interpretive Data

Interpretive Data: Background Information for Familial Transthyretin Amyloidosis (TTR) Sequencing:
Characteristics
: Familial Transthyretin Amyloidosis  is caused by pathogenic variants of the TTR gene resulting in abnormal amyloid accumulation in various tissues and is generally categorized into three phenotypes:  1) familial amyloid polyneuropathy, a slowly progressive sensorimotor and autonomic neuropathy; 2) familial amyloid cardiomyopathy, a restrictive cardiomyopathy with cardiomegaly, conduction block, angina, congestive heart failure and aortic dissection/dilatation; and 3) leptomeningeal amyloidosis, primarily affecting the CNS, causing dementia, visual impairment, seizures, ataxia, psychosis, hemorrhage, and hydrocephalus. TTR variants can also be associated with benign familial euthyroid hyperthyroxinemia.
Incidence: 1 in 568 individuals from Northern Portugal; 1 in 100,000 individuals of Northern European ancestry.
Inheritance: Autosomal dominant.
Penetrance: Incomplete.
Cause: Pathogenic TTR gene variants.
Clinical Sensitivity: 99 percent for Familial TTR Amyloidosis.
Methodology: Bidirectional sequencing of all coding regions and intron-exon boundaries of the TTR gene.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region variants, deep intronic variants and large deletions/duplications in TTR will not be detected.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Compliance Category

Laboratory Developed Test (LDT)

Note

Hotline History

N/A

CPT Codes

81404

Components

Component Test Code* Component Chart Name LOINC
2014036 TTR FGS Spec 31208-2
2014037 TTR FGS Interpretation 48033-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • Amyloidosis
  • Polyneuropathy
Familial Transthyretin Amyloidosis (TTR) Sequencing