41CDKL5 deficiency disorder (CDD) (CDKL5 缺乏症)
42Central Core Disease (CCD) (肌中央軸空症)
43Charcot-Marie-Tooth Disease - Type 2 (CMT2) (進行性神經性腓骨肌萎縮症第2型)
44Chronic Hemolytic Anemia (慢性溶血性貧血症)
45Chronic Inflammatory Demyelinating Polyneuropathy (CIPD) (慢性脫髓鞘性神經炎)
46Chronic Suppurative Osteomyelitis (慢性化膿性骨髓炎)
47Chronic thromboembolic pulmonary hypertension (CTEPH) (慢性血栓栓塞性肺高壓)
48CNS Vasculitis (腦血管炎)
49Cockayne Syndrome (柯凱因氏症侯群)
50Coenzyme Q10 Deficiency-7 (Genetic Disorder)
51Coffin Siris Sydrome (Coffin Siris綜合症)
52Collagen XII Myopathy (膠原蛋白XII缺失肌肉萎縮症)
53Complex Regional Pain Syndrome (CRPS) (複雜性局部疼痛症) / Reflex Sympathetic Dystrophy Syndrome (RSD) (交感神經失調症)
54Cone Dystrophy (錐細胞失養症)
55Cone-rod Dystrophy (視幹細胞營養不良症)
56Congenital Bile Acid Synthesis (CBAS) (胆汁酸合成障碍)
57Congenital Glaucoma (先天性青光眼)
58Congenital Insensitivity to Pain with Anhidrosis (CIPA) (先天性痛覺不敏感症合併無汗症)
59Congenital Muscular Dystrophy (CMD) (先天性肌营养不良症)
60Cornelia De Lange Syndrome (CdLS) (狄蘭氏症侯群)