Figure 2.

Sequencing of SCN5A mutations. (a) Automated DNA-sequencing electrophoretographs illustrating the two mutations segregating in each family (SS1, SS2, and SS6) are tiled vertically. (b) Schematic of the transmembrane topology of SCN5A illustrating the location of mutations found in congenital SSS families. Mutations are colored to indicate in which family they occur (orange circles = SS1, open circles = SS2, yellow circles = SS6). D1–D4 indicate homologous domains of the α subunit of the cardiac sodium channel.