Congenital thrombotic thrombocytopenic purpura associated with unilateral moyamoya disease.

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy disorder associated with congenital or acquired deficiency of the von Willebrand factor-cleaving protease, ADAMTS13. The central nervous system and kidneys are the two major organs of involvement in TTP. Moyamoya (puff of smoke) disease is a cerebral arteriopathy of unknown etiology characterized by narrowing or occlusion of the distal internal carotid or proximal anterior or middle cerebral arteries, which causes the formation of multiple tiny collateral networks. We report here a case of an 11-year-old boy with unilateral moyamoya disease and congenital TTP. The patient had a history of severe neonatal jaundice and thereafter recurrent episodes of hemolytic anemia associated with renal dysfunction and cerebral infarction. The plasma ADAMTS13 activity of the patient <3% of normal, and ADAMTS13 gene analysis revealed an abnormal splicing mutation (c.330+1 G > A) in one allele and a novel missense mutation (p.Ile1217Thr) in the other. This is the first case of a genetically confirmed congenital TTP associated with unilateral moyamoya disease. Although the causal relationship between the two diseases has not been established, TTP may be included as one of the causes of moyamoya syndrome.