Inherited thrombotic thrombocytopenic purpura in pregnancy.

OBJECTIVE

The primary pathologic reason for thrombotic thrombocytopenic purpura (TTP) lies in the systemic formation of platelet aggregations in association with endothelial cells damage. Endothelial damage is a result of an abnormal synthesis and metabolism of unusually large von Willebrand Factor (ULvWF) multimers. In normal conditions vWF cleaving metalloprotease, known as ADAMTS-13 (A Disintegrin And Metalloproteinase with Thrombospondin type-1 motif, member 13) prevents the ULvWF entrance in the circulation. It already has been proven that thrombotic thrombocytopenic purpura is strongly correlated with severe congenital or acquired deficiency of ADAMTS-13. Congenital ADAMTS-13 deficiency is known as Upshaw-Schulman Syndrome and it accounts for only 2-4% of all TTP cases. It is conditioned by genetic variants of the ADAMTS-13 gene causing reduced ADAMTS-13 synthesis and shows an autosomal recessive type of inheritance.

CASE PRESENTATION: We present an interesting case of a 20 year old patient, primigravida, nulliparous, in 28th gestational week of twin pregnancy with undiagnosed Upshaw-Schulman Syndrome. The patient was transferred from the district hospital to the Tertiary Perinatal Care Center because of thrombocytopenia and suspicion of hemolytic-uremic syndrome. Genetic analysis performed 5 years after patient's death (before 2008 that kind of genetic analysis had not been available in Poland) showed a homozygotic mutation in the ADMTS13 gene (4143insA) which confirmed the diagnosis of Upshaw-Schulman Syndrome.

CONCLUSIONS

1. TTP, especially hereditary Upshaw-Schulman Syndrome, is extremely rare and complicates the course of pregnancy. It is usually very sudden and dramatic; 2. Differential diagnosis of this disease is difficult and treatment strategy very burdensome for the patient. For this reason, diagnosis of micro-angiopathic disorders need to be simultaneously based on both clinical symptoms and laboratory findings; 3. Genetic diagnosis that confirms exact recognition of Upshaw-Schulman Syndrome is not commonly available; 4. The described case was a huge diagnostic challenge, and actually the final diagnosis was published until five years after the patient's death. Before 2008, that type of genetic analysis had not been available in Poland; 5. Despite the enormous progress in medical knowledge and experience, the exact diagnosis of TTP, including Upshaw-Schulman Syndrome, of this condition remains very difficult.