Karl Theodor Fahr (3 October 1877 – 29 October 1945) was a German pathologist born in Pirmasens of the Rhineland-Palatinate. In 1903 he earned his medical doctorate from the University of Giessen, afterwards continuing his studies with Eugen Bostroem (1850-1926) in Giessen, under Morris Simmonds (1855-1925) in Hamburg and with Ilya Ilyich Metchnikoff (1845-1916) in Paris. In 1924, he became director of the pathological institute at the University Medical Center Hamburg-Eppendorf. Fahr is remembered for his work in nephrology and research of kidney disorders. With internist Franz Volhard (1872-1950) he published a comprehensive monograph on Bright's disease titled Die Brightsche Nierenkrankheit. In 1923, he provided an early correlation between lung cancer (Bronchialkarzinom) and tobacco smoking. Today his name is associated with Fahr's disease, which is a degenerative neurological disorder characterized by calcifications and cell loss within the basal ganglia. Fahr was however not the first describe the disease and there are suggestions that the eponym be avoided. In 1933 Fahr signed the Vow of allegiance of the Professors of the German Universities and High-Schools to Adolf Hitler and the National Socialistic State. He committed suicide in 1945.

Selected writings