| Abbreviation | Definition |
|---|---|
| CDGS | Carbohydrate Deficient Glycoprotein Syndromes |
| CDLS | Cornelia De Lange Syndrome |
| CDTS | Chronic Drunk Text Syndrome |
| CECS | Canine Epileptoid Cramping Syndrome |
| CECS | Chronic Exertional Compartment Syndrome |
| CFC | Cardiofaciocutaneous (syndrome) |
| CHS | Cannabinoid Hyperemesis Syndrome |
| CHS | Captain Hook Syndrome |
| CHTS | Congenital Hypothyroidism Syndrome |
| CIRS | Chronic Inflammatory Response Syndrome |
| CIS | Clinically Isolated Syndrome |
| CLCD | Cleidocranial Dysostosis |
| CLCD | Cleidocranial Dysplasia |
| CLS | Coffin Lowry syndrome |
| CLSS | CENANI LENZ SYNDACTYLY SYNDROME |
| CMNS | congenital melanocytic nevus syndrome |
| CNCS | Cochleovestibular Nerve Compression Syndrome |
| COLTS | Compulsive Obsessive LUD Tracking Syndrome |
| CPTSD | Complex Post-Traumatic Stress Disorder |
| CREST | Calcinosis,Raynaud's phenomenon, Esophagial dysmotility, Sclerodactyly and Telangiectasia |