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Cardiac valvular anomalies in Fabry disease. Clinical, morphologic, and biochemical studies
Insights
Fabry disease causes heart problems due to a buildup of a substance called trihexosyl ceramide in cardiac tissues and blood vessels. This accumulation of glycosphingolipids leads to cardiovascular issues in affected individuals.
Area of Science:
- Biochemistry
- Cardiology
- Genetics
Background:
- Fabry disease is a rare genetic disorder.
- It results from a deficiency in the enzyme alpha-galactosidase A.
- This deficiency leads to the accumulation of glycosphingolipids.
Observation:
- Two hemizygous males with Fabry disease and mitral insufficiency were studied postmortem.
- Cardiac tissues and vessels showed anatomic, ultrastructural, and biochemical abnormalities.
- Accumulation of trihexosyl ceramide was observed in lysosomes of cardiac and vascular tissues.
Findings:
- Defective alpha-galactosidase A activity caused significant trihexosyl ceramide accumulation in all cardiac tissues, particularly the mitral valve and left ventricle.
- Digalactosyl ceramide, normally absent, was elevated in lung and right heart tissues.
- Vascular endothelium also showed trihexosyl ceramide accumulation.
Implications:
- Progressive trihexosyl ceramide accumulation in cardiac structures and the vascular system is directly linked to cardiovascular manifestations of Fabry disease.
- Understanding these mechanisms can inform therapeutic strategies for Fabry disease.
- This research highlights the critical role of lysosomal enzyme activity in cardiovascular health.
Abstract:
The cardiovascular abnormalities were investigated in two unrelated hemizygous males with Fabry disease who had clinical mitral insufficiency. Postmortem examination of their hearts revelaed anatomic, ultrastructural and biochemical abnormalities resulting from defective activity of the lysosomal enzyme, alpha-galactosidase A. The ultrastructural and biochemical studies demonstrated the marked accumulation of the major glycosphingolipd substrate, trihexosyl ceramide, in the lyosomes of all the cardiac tissues examined; the greatest concentrations were found in the mitral valve and elft ventricular myocardium. Intriguingly, digalactosyl ceramide, a glycosphingolipid substrate not detectable in normal lung, vessel or cardiac tissues, was found increased only in the lung and right heart tissues. Morphologic and chemical examination of cardiac and systemic vessels demonstrated accumulation of trihexosyl ceramide in lysosomes of the vascular endothelium. These studies demonstrate that the progressive accumulation of trihexosyl ceramide in the lysosomes of the cardiac structures and vascular system leads to the multiple cardiovascular manfiestation of Fabry disease.