21Anomalous Origin of the Left Coronary Artery from Pulmonary Artery (ALCAPA) (肺動脈左冠狀動脈異常症)
22Anomalous Origin of the Right Coronary Artery (AORCA) (右邊冠狀動脈畸形)
23Anti-MOG Associated Encephalomyelitis (抗MOG相關腦脊髓炎)
24Anti-NMDA Encephalitis (自體免疫性腦炎)
25Antisynthetase Syndrome (抗合成酶綜合症)
26Apert Syndrome (亞伯氏症)
27Aplastic Anemia (再生不良性貧血症)
28Aromatic L-amino Acid Decarboxylase Deficiency (AADC) (芳香族L-胺基酸類脫羧基酶缺乏症)
29Arthrogryposis Multiplex Congenita (AMC) (先天性多發性關節攣縮症)
30ASH1L (Genetic Disorder)
31ATAD3A Syndrome (Genetic Disorder)
32ATR-X Thalassemia Syndrome (ATRX) (α地中海贫血X-連鎖智力障碍症)
33Atypical Hemolytic Uremic Syndrome (aHUS) (非典型溶血性尿毒症)
34Atypical Parkinsonism (非典型帕金森病)
35Autoimmune Insulin Syndrome (胰島素自身免疫綜合症)
36Autosomal Recessive Polycystic Kidney Disease (ARPKD) (常染色體隱性多囊腎)
37Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) (Charlevoix-Saguenay型隐性痙攣性共濟失調症)
38Beckwith-Wiedemann Syndrome (BWS) (貝克威思-威德曼症候群)
39Behcet's Disease (BD) (貝賽特氏症)
40Bilateral Perisylvian Polymicrogyria (BPP) (雙側西耳維厄斯周圍多小腦回畸形症)