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Homocystinuria presenting as multiple arterial occlusions
Insights
Pyridoxine-responsive homocystinuria can cause arterial occlusions, even without typical symptoms. Early screening is crucial for patients with unexplained vascular issues, especially during pregnancy.
Area of Science:
- Medical Genetics
- Vascular Medicine
- Metabolic Disorders
Background:
- Homocystinuria is an inherited metabolic disorder.
- Pyridoxine (Vitamin B6) is a cofactor for enzymes involved in homocysteine metabolism.
- Unusual vascular events can be a manifestation of homocystinuria.
Observation:
- A patient presented with multiple arterial occlusions post-pregnancy, lacking other common homocystinuria signs.
- Family screening confirmed autosomal recessive inheritance of homocystinuria.
- Platelet function and vascular biopsies were normal in affected individuals.
Findings:
- The patient's arterial occlusions were linked to pyridoxine-responsive homocystinuria.
- Pregnancy may precipitate thrombotic events due to increased fetal nutrient demand.
- The precise mechanism for thrombotic complications in this case remains unclear.
Implications:
- Suggests screening for homocystinuria in patients with unexplained arterial occlusions, irrespective of other symptoms.
- Highlights the potential role of pregnancy in unmasking metabolic disorders like homocystinuria.
- Emphasizes the need for further research into the thrombotic mechanisms of homocystinuria.
Abstract:
We describe a patient with pyridoxine-responsive homocystinuria who presented with multiple arterial occlusions after pregnancy but who showed no other stigmata of the disease and we suggest that in patients with unusual vascular lesions, screening for homocystinuria should be carried out even in the absence of the other manifestations of the condition. Family screening showed that her brother was also affected but that their children were not, confirming the autosomal recessive model of inheritance. We found the index case to have normal platelet behaviour; both she and her brother had normal veins and arteries on biopsy, so the mechanisms underlying the thrombotic complications remain uncertain. It seems likely that pregnancy contributed to the time of onset of the thrombotic complications in the index case, because of the foetal demands for pyridoxine or folate during gestation.