Figure 1. Clinical details of carrier pairs in Cleveland LQT2 family.

Zoomed-in snapshot of the family pedigree that focuses on 5 individuals of the family we used to generate the carrier pairs along with their relevant patient history (see Methods for in-depth explanation of patient selection and phenotype binning criteria and Supplemental Table 2 for clinical details on all 26 R752W mutation–positive individuals). Individuals are referenced first by the generation number and then by the family member number, read from left to right (e.g., IV-3 is generation 4, family member 3). This reference system is used throughout the paper. The black square is the hERG mutation negative healthy male control. Blue circles and squares are females and males, respectively, who are mildly-affected-phenotype hERG R752W mutation–positive relatives. Red circles and squares are severely-affected-phenotype hERG R752W mutation–positive relatives. Hatched circles and squares are females and males, respectively, who are hERG R752W-carrying individuals who are not fully characterized in this study.