| GENE | LOCUS or SYNDROME | AMINO ACID CHANGE | NUCLEOTIDE CHANGE | EXON | ETHNICITY (Number of families) | REFERENCES |
| KCNE1/IsK | Jervell and Lange-Nielson Syndrome | T7I | 20C>T | exon 3 | Lebanese (1) | Schulze-Bahr 1997 |
| (Homozygous or compound heterozygous) | V47F | 139G>T | exon 3 | N/A (1) | Bianchi 1999 | |
| L51H | 151TG>AT | exon 3 | N/A (1) | Bianchi 1999 | ||
| T59P, L60P | 172A>C, 176TG>CT | exon 3 | British (1) | Tyson 1997 | ||
| D76N | 226G>A | exon 3 | Lebanese (1); North American (1) | Schulze-Bahr 1997; Duggal 1998 | ||
| Long QT Syndrome | R32H | 95G>A | exon 3 | N. American/European | Splawski 2000 | |
| (Heterozygous) | S74L | 221C>T | exon 3 | N/A (1) | Splawski 1997 | |
| D76N | 226G>A | exon 3 | N/A (1); N. American (1) | Splawski 1997; Duggal 1998 | ||
| W87R | 259T>C | exon 3 | N/A (1) | Bianchi 1999 | ||
| R98W | 292C>T | exon 3 | N. American/European (1) | Splawski 2000 | ||
| V109I | 325G>A | exon 3 | White (1) | Schulze-Bahr 2001* | ||
| *Mild form | ||||||
| P127T | 379C>A | exon 3 | N. American/European (1) | Splawski 2000 |