homocystinuria_flashcards
What is homocystinuria?
A rare autosomal recessive disease caused by a deficiency of cystathionine beta synthase.
What causes homocystinuria?
A deficiency of cystathionine beta synthase, resulting in severe elevations in plasma and urine homocysteine concentrations.
What are the musculoskeletal features of homocystinuria?
Marfanoid body habitus, arachnodactyly, osteoporosis, kyphosis.
What are the neurological features of homocystinuria?
Learning difficulties, seizures.
What are the ocular features of homocystinuria?
Downwards (inferonasal) dislocation of lens, severe myopia.
What other features are associated with homocystinuria?
Fine, fair hair, malar flush, livedo reticularis.
What are the risks associated with homocystinuria?
Increased risk of arterial and venous thromboembolism.
What investigations are used to diagnose homocystinuria?
Increased homocysteine levels in serum and urine, cyanide-nitroprusside test (also positive in cystinuria).
What is the treatment for homocystinuria?
Vitamin B6 (pyridoxine) supplements.
