| Abbreviation | Definition |
|---|---|
| KS | Klinefelter syndrome |
| KSS | Kearns Sayre Syndrome |
| KTS | Klippel Trenaunay Syndrome |
| KTW | KlippelTrenaunayWeber syndrome |
| KWS | Kimmelstiel Wilson Syndrome |
| LAMS | Look At Me Syndrome |
| LBDS | Liver Blood Deficiency Syndrome |
| LBS | Loaded Bladder Syndrome |
| LBS | Loose Butthole Syndrome |
| LCCS | Lethal Congenital Contracture Syndrome |
| LCWS | Linda Cohn Withdrawal Syndrome |
| LDSA | Lebanese Down Syndrome Association |
| LDSA | London Down Syndrome Association |
| LEMS | Lambert Eaton Myasthenic Syndrome |
| LFS | Lavender Foal Syndrome |
| LFS | Li Fraumeni Syndrome |
| LGL | LownGanongLevine syndrome |
| LGL | Lown–Ganong–Levine syndrome |
| LGS | Lennox Gastaut Syndrome |
| LGS | LennoxGastaut syndrome |