GeneDx :: Tests :: Transthyretin Amyloidosis: Familial Amyloid Polyneuropathy and Familial Amyloid Cardiomyopathy

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Transthyretin Amyloidosis: Familial Amyloid Polyneuropathy and Familial Amyloid Cardiomyopathy

Transthyretin (TTR) amyloidosis is an autosomal dominant disorder caused by the deposition of insoluble amyloid fibrils around peripheral nerves and in various tissues, including the heart muscle. Based on the predominant organ involvement, several distinct subtypes have been reported:

Familial amyloid polyneuropathy (FAP) aka TTR amyloid neuropathy is characterized by slowly progressive, peripheral sensorimotor polyneuropathy and autonomic dysfunction. Disease onset is usually in the third to fourth decade of life.

Leptomeningeal amyloidosis aka oculoleptomeningeal amyloidosis affects predominantly the central nervous system, sometimes combined with visual impairment.

Cardiac amyloidosis usually manifests in the sixth decade of life with progressive left ventricular hypertrophy and restrictive cardiomyopathy. In a subset of families with cardiac amyloidosis, peripheral neuropathy may be completely absent or very mild.

TTR is the only gene associated with transthyretin amyloidosis. The vast majority of individuals with transthyretin amylodosis (forms with polyneurogenic as well as cardiomyopathy) are expected to have a mutation in TTR that is detectable by DNA sequence analysis. If a mutation is present in the TTR gene, sequence analysis as performed at GeneDx is expected to detect >99% of the mutations identifiable by sequencing.

Using genomic DNA obtained from a venous blood sample (1-5 mL in EDTA), GeneDx will perform bi-directional sequence analysis of the complete coding region (exons 1-4) of the TTR gene. This analysis is expected to identify most types of mutation, if one exists, with the exception of genomic deletions, duplications or rearrangements. In circumstances when such a gene deletion or duplication is suspected, ExonArrayDx is available to determine the copy number at exon-level resolution for the TTR gene.

Information Sheet, including prices and CPT codes (TTR)
Consent Document (TTR)
Genetic Test Sample Submission Form (Test Requisition Form) including Payment Options

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