Primary Hyperoxaluria, Type 1 (AGXT)
Primary hyperoxaluria, type 1 is an autosomal recessive, pan-ethnic disease caused by pathogenic variants in the AGXT gene. Age of onset is usually between 1 and 25 years of age, although approximately 10% can present with a severe form before six months of age, and some patients may present later in adulthood. Severity varies with age of onset, but clinical features typically include the accumulation of oxalate in various organs, specifically the kidney, which leads to the development of kidney stones and progressive kidney failure. Other features include oxalate accumulation in the bones and the eyes, leading to bone pain, fractures, and vision impairment. If untreated, kidney disease will eventually lead to death from renal failure, usually in young adulthood. However, the age that the patient reaches end-stage kidney disease is widely variable depending on age of onset. A genotype-phenotype correlation has not been reported for disease severity, but specific variants are associated with B6 responsiveness, which can direct the course of treatment.
For information about carrier frequency and residual risk, please see the Expanded Carrier Screen brochure.