Homocystinuria is a rare congenital disorder of metabolism.

Clinical presentation

The disease may affect one or more of the systems below :


A deficiency of the enzyme cystathionine-β-synthase causes classic homocystinuria whereby the metabolism of homocysteine to methionine is affected. It is inherited in a autosomal recessive fashion. Other forms of secondary homocystinuria can be seen in other rare inborn metabolism disorders (e.g. methylenetetrahydrofolate reductase deficiency) .


High levels of plasma total homocysteine and methionine are present . Neonatal screening heel-prick tests typically include testing for homocystinuria.

Genetic testing

Genetic testing can be used to confirm homocysteinuria.

Radiographic features

No radiographic features are specific for homocystinuria and the diagnosis is made through genetic and laboratory testing. Rarely, some associations of the disease may be visible on imaging (e.g. spontaneous pneumothorax or thromboembolism) .


Although not specific, MRI brain may show :

  • multiple cortical-subcortical infarctions in the cerebellar and cerebral hemispheres of varying ages
  • diffuse white matter signal intensity abnormalities may be present secondary to demyelination
  • occlusive vessel or dural sinus disease on MR angiography or venography
  • lens dislocation

Treatment and prognosis

Mortality in homocystinuria mostly occurs from premature cardiovascular disease .

Differential diagnosis

Siehe auch: