How FAMILION Works
The FAMILION test is designed to identify mutations in ion channel genes in patients and their family members with inherited cardiac channelopathies such as Long QT Syndrome (LQTS), Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) and Brugada Syndrome (BrS). There is also evidence that mutations in these same genes may cause a percentage of  Familial Atrial Fibrillation, Short QT Syndrome, Idiopathic Ventricular Fibrillation, Progressive Cardiac Conduction Disease, Congenital Sick Sinus Syndrome and Sudden Infant Death Syndrome (SIDS).

Description of the Tests
The FAMILION tests provide analysis of subsets of six major cardiac ion channel genes. This analysis includes sequence determination and variant detection (i.e. mutations and polymorphisms) in open reading frames  and intronic sequences containing splice junction sites. Sequencing is performed in both forward and reverse directions for most regions using dye-terminator chemistries.

The following genes can be ordered:

The test can be ordered in four configurations:

• LQTS Test provides analysis for variants in the KCNQ1, KCNH2, SCN5A, KCNE1 and KCNE2 genes and is indicated when there is a high index of suspicion of disease such as stress-induced syncope, prolonged QT interval, family history of sudden cardiac death and/or unexplained VT/VF or TdP.
• BrS Test provides analysis for variants only for the SCN5A gene and is appropriate in cases of suspected Brugada Syndrome
• CPVT Test provides analysis for variants only for the RYR2 gene and is indicated in cases of suspected Catecholaminergic Polymorphic Ventricular Tachycardia.
• Family Specific Test provides analysis of one or more mutations found in an index case using any of the above test configurations or confirmed results from another laboratory and is indicated for testing blood relatives of patients with a positive LQTS, BrS, or CPVT test. Please see Technical Specifications.

Test Results

DNA variants are identified and classified by comparison with reference sequences and the PGxHealth Cardiac Ion Channel Variant Database. This database is produced through review of published literature and PGxHealth’s sequencing. This database also contains an extensive collection of common polymorphisms and rare variants in these genes that are not expected to confer susceptibility to congenital arrhythmia syndromes; these variants were found in comprehensive scanning of the genes in several hundred individuals of diverse race and ethnicity or from study of the literature, together referred to as the “Reference Panel.” The healthy individuals in the Reference Panel were not known to have LQTS, Brugada Syndrome, CPVT or related syndromes. An expert scientist ensures variant classification and interpretation reflect current, published information.

All variants found are classified as to their disease-causing potential and reported to the referring physician.

The FAMILION test results alone should not be used to exclude the diagnosis of a cardiac channelopathy. It is estimated that detectable variants in these 5 genes account for up to 75% of cases of familial LQTS, 50-55% of CPVT and 15-20% of BrS.

The FAMILION tests are performed by Cogenics, Inc. (5 Science Park, New Haven, CT 06511), a CLIA licensed laboratory.

For more information about FAMILION, you can download a copy of our FAMILION^® Technical Specifications Document

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