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Platelet survival and morphology in homocystinuria due to cystathionine synthase deficiency
Insights
Platelet survival in homocystinuria patients is normal, contrary to previous findings. This study found no increased platelet vacuolization, suggesting alternative mechanisms for thrombosis in this condition.
Area of Science:
- Biochemistry
- Hematology
- Genetics
Background:
- Homocystinuria, caused by cystathionine synthase deficiency, is linked to significant thromboembolism.
- Previous research suggested shortened platelet survival and increased vacuolization in affected patients.
Purpose of the Study:
- To investigate platelet survival and morphology in patients with homocystinuria.
- To clarify the discrepancy with prior studies regarding platelet abnormalities.
Main Methods:
- Studied platelet survival in six homocystinuria patients.
- Examined platelet morphology via electron microscopy in patients and heterozygotes.
- Compared findings to normal control subjects.
Main Results:
- Platelet survival was within normal limits (mean 9.75+/-0.94 days).
- Electron microscopy revealed no increased platelet vacuolization in patients or heterozygotes.
- Results contrast with previous reports suggesting platelet abnormalities.
Conclusions:
- The mechanism of thrombosis in homocystinuria requires further investigation.
- Discrepant findings may stem from genetic heterogeneity or technical differences.
- Platelet abnormalities may not be the primary driver of thrombosis in all homocystinuria cases.
Abstract:
In homocystinuria due to cystathionine synthase deficiency thromboembolism is a major cause of mortality and morbidity. Recent studies by others identified an abnormally shortened platelet survival and increased platelet vacuolization in patients with homocystinuria. When we studied six additional patients, however, we found the platelet survival to be within normal limits for each. The mean survival (+/-1 S.D.) was 9.75+/-0.94 days (normal, 9.27+/-1.06). In addition, platelets from five patients with homocystinuria and three obligate heterozygotes could not be distinguished from those of seven normal control subjects by electron microscopy. Specifically, no increased vacuolization was observed. Genetic heterogeneity, technical differences of differences in plasma homocystine concentrations could account for these descrepant results. The mechanism of thrombosis in homocystinuria remains an open question.