This is a list of diseases starting with the letter "J".

Ja–Je

  • Jackson–Weiss syndrome
  • Jacobsen syndrome
  • Jadassohn–Lewandowsky syndrome
  • Jaffer–Beighton syndrome
  • Jalili syndrome
  • Jancar syndrome
  • Jankovic–Rivera syndrome
  • Jansen type metaphyseal chondrodysplasia
  • Jansky–Bielschowsky disease
  • Japanese encephalitis
  • Jarcho–Levin syndrome
  • Jejunal atresia
  • Jensen syndrome
  • Jequier–Kozlowski skeletal dysplasia
  • Jervell and Lange-Nielsen syndrome
  • Jeune syndrome situs inversus
  • Jeune syndrome
  • Jeune asphyxiating thoracic dystrophy

Jo

  • Job syndrome
  • Johanson–Blizzard syndrome
  • Johnson–Hall–Krous syndrome
  • Johnson–Munson syndrome
  • Johnston–Aarons–Schelley syndrome
  • Jones–Hersh–Yusk syndrome
  • Jones syndrome
  • Jorgenson–Lenz syndrome
  • Joseph disease
  • Joubert syndrome bilateral chorioretinal coloboma
  • Joubert syndrome

Ju

  • Juberg–Hayward syndrome
  • Juberg–Marsidi syndrome
  • Judge–Misch–Wright syndrome
  • Jumping Frenchmen of Maine
  • Jung–Wolff–Back–Stahl syndrome
  • Juvenile dermatomyositis
  • Juvenile gastrointestinal polyposis
  • Juvenile gout
  • Juvenile hyaline fibromatosis
  • Juvenile macular degeneration hypotrichosis
  • Juvenile muscular atrophy of the distal upper limb
  • Juvenile myoclonic epilepsy
  • Juvenile nephronophthisis
  • Juvenile rheumatoid arthritis
  • Juvenile temporal arteritis
  • Juliannite nephronophthisis