homocystinuria
Pronunciation: ho-mo-SIS-tin-YUR-ee-ah
Inherited disorder of methionine metabolism causing elevated homocysteine levels.
Full Definition
An autosomal recessive disorder most commonly caused by deficiency of cystathionine beta-synthase, leading to accumulation of homocysteine and methionine. Classical homocystinuria can cause intellectual disability, skeletal abnormalities, lens dislocation, and thromboembolic events if untreated. Newborn screening detects this condition through elevated methionine levels in dried blood spots. Some forms are responsive to vitamin B6 (pyridoxine) therapy, while others require dietary methionine restriction and cysteine supplementation. Early detection and treatment can prevent most complications.
Usage
Usage note: Distinguish from homocysteinemia, which refers to elevated homocysteine specifically.
In Context
- "Elevated methionine levels prompted additional testing to confirm suspected homocystinuria." — Laboratory protocol
- "B6-responsive homocystinuria shows dramatic improvement with pyridoxine supplementation." — Treatment case study