(ALD)

Very rare: unknown prevalence but probably underestimated. Caused by mutations that interfere with the synthesis or the action of thromboxane A2 and produce a common phenotype: a decrease in platelet aggregability.

There are three subgroups:

-        platelet prostaglandin endoperoxide synthetase 1 or COX1 deficiency [MIM 605 735]: gene PTGS1 (9q33.2)

• thromboxane synthase deficiency [MIM 274 180]: autosomal recessive transmission of a mutation of the TBAXS1 gene (7q34)
• TBXA2 receptor deficiency [MIM 188 070]: autosomal dominant transmission of a mutation of the TBAX2R gene (19p13.3)

Clinical presentation: hemorrhagic signs are reported by only about 60 % of patients: frequent hematomas or epistaxis, post-surgical bleeding (amygdalectomy, dental extractions), menorrhagia

Diagnosis: decreased platelet aggregation in the presence of arachidonic acid or ADP (10 % in severe form, 19-32 % in moderate form).

Anesthetic implications: 

NAID's are contraindicated; in case of bleeding: platelet transfusion. Tranexamic acid in prophylaxis ?

References : 

-         Rolf N, Knoefler R, Bugert P, Gehrisch S et al.
Clinical and laboratory phenotypes associated with the aspirin-like defect: a study in 17 unrelated families.
Br J Haematol 2008 ; 144 : 416-24.

Updated: December 2020