Fig. 2: The ABC system can be used independently or as an add-on to the ACMG-based classification system.
From: Stepwise ABC system for classification of any type of genetic variant
In the latter case, the VUS class is given a 0 (fVUS) or 3 (HFE) grade in step A of the ABC system, other classes are kept (P = 5, LP = 4, LB = 2, and B = 1). In the second step B of the ABC system, the issue is really how well the genotype and phenotype match, from 0 (no conceivable correlation) to 5 (perfect match). The combined class is given by the steps A and B grading and divided into seven classes: 0 if no step B grading was deemed necessary, and A–F if step B has been done after step A. In step C (optional), each class can be linked to the standard comments that best addresses the clinical question.
