X-Linked Agammaglobulinaemia see Primary Immunodeficiencies
X-Linked Hypophosphatemia
X-Linked Ichthyosis see Ichthyosis
X-Linked Lymphoproliferative syndrome see Primary Immunodeficiencies
Xanthine Oxidase/Sulphite Oxidase Deficiency see Metabolic diseases
Xanthinuria deficiency see Purine & Pyrimidine Metabolic diseases
Xeroderma Pigmentosum
XLA see Primary Immunodeficiencies
XLP see Primary Immunodeficiencies
XO syndrome see Turner syndrome
XOD see Purine & Pyrimidine Metabolic diseases
XP see Xeroderma Pigmentosum
XXX see Triple-X syndrome
XXXXY see Klinefelter syndrome
XXXY see Klinefelter syndrome
XXY see Klinefelter syndrome
XYY syndrome