Test ID: ATNGS    
Antithrombin Deficiency, SERPINC1 Gene, Next-Generation Sequencing, Varies

Ascertaining a causative alteration in SERPINC1 and the affected region of antithrombin (AT) protein in an individual clinically diagnosed with antithrombin deficiency

Genetic confirmation of a clinical AT deficiency diagnosis, particularly in patients with borderline low AT activity levels

Prognosis and risk assessment based on the genotype-phenotype correlations

Ascertaining alteration status of family members related to an individual with a confirmed SERPINC1 alteration for the purposes of informing clinical management and genetic counseling

Evaluating individuals with apparent heparin resistance

This test is not intended for prenatal diagnosis

This test detects pathogenic alterations in the SERPINC1 gene to delineate the underlying molecular defect in a patient with a laboratory diagnosis of antithrombin (AT) deficiency based on a reduced AT activity or antigen.

The gene target for this test is:

Gene name (transcript): SERPINC1 (GRCh37 [hg19] NM_000488)

Chromosomal location: 1q25.1

The clinical workup for antithrombin deficiency begins with an antithrombin (AT) activity assay (see ATTF / Antithrombin Activity, Plasma). An abnormal result is considered less than 80% of normal activity.

Genetic testing for AT deficiency is indicated if:

-AT activity assay is less than 80%

-There is a clinical suspicion for hereditary deficiency of antithrombin due to family history or atypical clinical presentation

If AT activity results are abnormal, an antithrombin antigen assay is usually performed to determine the quantity of antithrombin present (ATTI / Antithrombin Antigen, Plasma). This is done to distinguish between type I AT deficiency (characterized by reduced AT activity and antigen) and type II AT deficiency (low activity and normal antigen).

• Informed Consent for Genetic Testing
• Informed Consent for Genetic Testing (Spanish)
• Rare Coagulation Disorder Patient Information

Custom Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger sequencing when appropriate