241Vogt-Koyanagi-Harada Disease (VKH Disease) (原田氏病)
242von Hippel-Lindau Disease (VHL Disease) (希佩爾-林道病)
243Waardenburg Syndrome (WS) (瓦登伯革氏症侯群)
244Waldenstrom's Macroglobulinemia (WM) (華氏巨頭蛋白血症)
245Walker-Warburg Syndrome (WWS) (Walker-Warburg綜合症)
246WDR45 (Genetic Disorder)
247Wells Syndrome (韋爾斯綜合症)
248West Syndrome-Infantile Spasms (韋氏症-嬰兒痙攣症)
249Williams Syndrome (WS) (威廉氏症候群)
250Wilson's Disease (WD) (威爾遜氏症)
251Wolf-Hirschhorn Syndrome (WHS) (沃夫-賀許宏氏症候群)
252Wolfram Syndrome (Wolfram症候群)
253Worster-Drought Syndrome (WDS)
254WWOX Syndrome (Genetic Disorder)
255Xeroderma Pigmentosum (XP) (著色性乾皮症)
256X-linked Agammaglobulinemia (XLA) (X-連鎖無丙種球蛋白血症)
257X-linked Hypophosphatemic Rickets (XLH) (性聯遺傳型低磷酸鹽佝僂症)
258X-linked Myotubular Myopathy (XLMTM) (肌小管病變)
259X-linked Retinoschisis (XLRS) (Genetic Disorder)
260X-linked Thrombocytopenia (XLT) (Genetic Disorder)