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Inherited antithrombin III deficiency and cerebral thrombosis in a child
Insights
A family with antithrombin III (AT-III) deficiency experienced recurrent thrombosis. This quantitative AT-III deficiency, characterized by low AT-III activity and antigen levels, was identified in a 15-year-old boy and his relatives.
Area of Science:
- Hematology
- Genetics
- Clinical Medicine
Background:
- Antithrombin III (AT-III) is a crucial protein in the blood coagulation cascade.
- AT-III deficiency is a known risk factor for thromboembolic events.
Observation:
- A 15-year-old male presented with cerebral thrombosis, followed by recurrent lower extremity thrombosis.
- His mother and sister were also identified with similar symptoms and laboratory findings.
Findings:
- Quantitative AT-III deficiency was confirmed through decreased biological activity (AT-IIIc) and antigen levels (AT-IIIag) in affected family members.
- Crossed immunoelectrophoresis (CIE) showed normal migration patterns, suggesting a quantitative rather than qualitative defect.
- Warfarin therapy increased AT-III activity and antigen levels in affected individuals.
Implications:
- This case highlights a hereditary quantitative antithrombin III deficiency.
- Individuals with AT-III deficiency are at increased risk for thromboembolic disease, even in childhood.
- Understanding AT-III deficiency is critical for managing thrombotic risks in affected families.
Abstract:
Identification of a family affected by antithrombin III-heparin cofactor (AT-III) deficiency was made after diagnosis of the index case, a 15-year-old boy who suffered cerebral thrombosis. The proband had a two-year history of recurrent thrombosis involving the lower extremities. His mother and sister were also affected. Studies showed a decreased biological activity (AT-IIIc) and antigen (AT-IIIag) by the Laurell technique in the proband (AT-IIIc = 0.32, AT-IIIag = 46%), his sister (AT-IIIc = 0.29, AT-IIIag = 47%), and his mother (AT-IIIc = 0.41, AT-IIIag = 56%). Crossed immunoelectrophoresis (CIE) of the affected individuals' plasma in agarose-containing heparin demonstrated a normal pattern of migration. Treatment with warfarin sodium (Coumadin) resulted in an increase in activity in two of three affected family members, and in antigen in all three. Anticoagulant therapy did not affect the pattern of AT-III on CIE. This family represents a quantitative deficiency in antithrombin III. A review of the reported cases of antithrombin III deficiency indicates that individuals with this disorder may have thromboembolic disease in childhood.