THIRD EDITION
Factsheet
Condition:
Homocystinuria
Inheritance:
Autosomal recessive
Genetic Etiology:
Mutation in CBS gene, encoding cystathionine beta-synthase.
Frequency:
1/200,000 – 1/300,000
Clinical features:
Homocystinuria is a multisystem disorder, leading to myopia, lens dislocation, tall, slender body habitus, thromboembolism, and neurological impairment (developmental delay, seizures, movement disorder).
Management:
Some are responsive to pyridoxine treatment; treatment with betaine, folate, and vitamin B12; maintenance of methionine-restricted diet; supportive care.
Genetic counseling:
Based on autosomal recessive inheritance; molecular genetic testing available. Detectable by newborn screening, allowing early institution of dietary and medical management.