Primary hyperoxaluria type 1 (PH1) is an inherited disorder that is caused by the deficiency of a liver enzyme named alanine:glyoxylate-aminotransferase (AGT). People with PH1 have excessive accumulation of insoluble calcium salts in various tissues of the body, especially the kidney. PH1 causes recurrent kidney stones, which, if untreated, can cause life-threatening kidney failure. Other complications include short stature, vision loss, heart block, and bone and nerve pain. Onset of symptoms begins before 4-6 months for about one fifth of affected individuals. For the majority of affected individuals, symptoms begin in late childhood or early adolescence; the remaining affected individuals do not have symptoms until adulthood. Intellect is not affected by PH1. PH1 may be treated by high doses of vitamin B6 in some affected people. Organ transplantation of the liver and kidneys may treat or perhaps cure this disease. PH1 is caused by pathogenic variants in the AGXT gene.