Homocystinuria: clinical features

Genetics and biochemistry

• This is an in-born error of sulphur metabolism
• It is caused by a genetic deficiency of cystathionine beta-synthase (CBS)
• This enzyme converts homocysteine to cystathionine
• It may also be caused by methylene tetrahydrofolate reductase (MTHFR) deficiency
• The transmission is autosomal recessive

References

1. Morris AA, Kožich V, Santra S, et al. Guidelines for the diagnosis and management of cystathionine beta-synthase deficiency. J Inherit Metab Dis 2017; 40:49-74. 
2. Woods E, Dawson C, Senthil L, Geberhiwot T. Cerebral venous thrombosis as the first presentation of classical homocystinuria in an adult patient. BMJ Case Rep 2017; pii: bcr2016217477. 
3. Bishop L, Kanoff R, Charnas L, Krenzel C, Berry SA, Schimmenti LA. Severe methylenetetrahydrofolate reductase (MTHFR) deficiency: a case report of nonclassical homocystinuria. J Child Neurol 2008; 23:823-828.
4. Oliveira Santos M, Geraldes R, Conceição I. Peripheral nerve involvement in classic homocystinuria: an unusual association. BMJ Case Rep 2016; pii: bcr2016216255. 
5. Mulvihill A, Yap S, O'Keefe M, Howard PM, Naughten ER. Ocular findings among patients with late-diagnosed or poorly controlled homocystinuria compared with a screened, well-controlled population. J AAPOS 2001; 5:311-315.
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Related checklists

• Homocystinuria: differential diagnosis
• Homocystinuria: management
• Homocystinuria: surveillance
• Methylene tetrahydrofolate reductase (MTHFR) deficiency