Autosomal recessive
Caused by changes in both copies of CTH, which encodes cystathionase (cystathionine gamma-lyase), an enzyme needed to convert methionine into cysteine. Reduced enzyme activity lets cystathionine build up and spill into the urine.
Signs and symptoms
Symptoms vary widely. Some children have had mild to severe neurological symptoms, and it has been debated whether the condition is a disease or only a biochemical finding.
What a diagnosis changes
Treatment with vitamin B6 (pyridoxine) can normalise the biochemical findings, but clinical improvement has not been clearly shown. Genetic counselling is available.
Genes analysed
Also known as
cystathionase deficiency; cystathioninuria (disease); gamma-cystathionase deficiency
