| Abbreviation | Definition |
|---|---|
| LGS | Lennox–Gastaut syndrome |
| LKS | Landau Kleffner Syndrome |
| LLS | Leigh Like Syndrome |
| LOCS | Lack Of Creativity Syndrome |
| LOMS | Loving Old Man Syndrome |
| LPHAS | Limb/Pelvis-Hypoplasia/Aplasia Syndrome |
| LPHS | Loin Pain Hematuria Syndrome |
| LPS | Lost Pictograph Syndrome |
| LSS | Lumang Song Syndrome |
| LSSN | Lynch Syndrome Screening Network |
| LUS | Lavender Unicorn Syndrome |
| LUTS | Lower Urinary Tract Syndrome |
| LWFS | Lethal White Foal Syndrome |
| LWS | Last Word Syndrome |
| MAIS | Mild Androgen Insensitivity Syndrome |
| MALS | Median Arcuate Ligament Syndrome |
| MBS | Myles Bowel Syndrome |
| MCAS | Mast cell activation syndrome |
| MCNS | Minimal Change Nephrotic Syndrome |
| MDDS | Mitochondrial DNA depletion syndrome |