Congenital thrombotic thrombocytopenic purpura associated with unilateral moyamoya disease

Unusual presentation of acquired thrombotic thrombocytopenic purpura (TTP) versus catastrophic antiphospholipid syndrome in a patient with Moya-Moya disease, case report, and literature review

Coincidences in medicine are not so common. We are presenting a case of a patient diagnosed with Moya-Moya disease and antiphospholipid syndrome (APS) who presented with clinical and laboratory characteristics of catastrophic APS versus TTP. The diagnosis was a challenge because characteristics were overlapping. Nevertheless, a decision to treat the patient for TTP was made with afterward improvement. MMD has been associated with multiple immune disorders; however, only one case of acquired thrombotic thrombocytopenic purpura has been documented in association with this disease. None has been associated with catastrophic antiphospholipid syndrome. We are presenting a challenging case where all these three medical conditions were present at the same time.

A case of Moyamoya disease complicated by aHUS in a patient with a history of marginal zone B-cell lymphoma: lightning strikes thrice?

Atypical haemolytic uraemic syndrome (aHUS) is a rare, acquired thrombotic microangiopathy, mediated by complement activation, in very sick patients. Moyamoya is similarly a rare disease in which stenosis or occlusion of segment(s) of the anterior cerebral circulation leads to the formation of many thin collaterals. Other reports have described an association between HUS and Moyamoya disease in the paediatric population. However, this case study presents the exceptionally rare presentation of an adult with aHUS and Moyamoya disease in a patient who was treated with rituximab for marginal zone B-cell lymphoma.

A new horizon of moyamoya disease and associated health risks explored through RNF213

The cerebrovascular disorder moyamoya disease (MMD) was first described in 1957 in Japan, and is typically considered to be an Asian-specific disease. However, it is globally recognized as one of the major causes of childhood stroke. Although several monogenic diseases are known to be complicated by Moyamoya angiopathy, the ring finger protein 213 gene (RNF213) was identified as a susceptibility gene for MMD. RNF213 is unusual, because (1) it induces MMD with no other recognizable phenotypes, (2) the RNF213 p.R4810K variant is an Asian founder mutation common to Japanese, Korean and Chinese with carrier rates of 0.5–2 % of the general population but a low penetrance, and (3) it encodes a relatively largest proteins with a dual AAA+ ATPase and E3 Ligase activities. In this review, we focus on the genetics and genetic epidemiology of RNF213, the pathology of RNF213 R4810K, and the molecular functions of RNF213, and also address the public health contributions to current unresolved issues of MMD. We also emphasize the importance of a more updated definition for MMD, of qualified cohort studies based on genetic epidemiology and an awareness of the ethical issues associated with genetic testing of carriers.

Congenital ADAMTS13 deficiency: a rare mimicker of immune thrombocytopenic purpura

Congenital ADAMTS13 deficiency is a rare disease that leads to recurrent episodes of thrombotic thrombocytopenic purpura. We report a case that mimicked a recurring immune thrombocytopenic purpura in a child. Mild cases of ADAMTS13 deficiency may be initially confused with immune thrombocytopenic purpura if hemolytic anemia is not severe and renal or neurological symptoms are not present. Fresh frozen plasma is the treatment of choice in acute thrombotic thrombocytopenic purpura in ADAMTS13-deficient patients. The best long-term treatment for slightly symptomatic cases remains to be elucidated. Recombinant human ADAMTS13 factor will be a promising option when commercially available.

Long term follow up of congenital thrombotic thrombocytopenic purpura (Upshaw-Schulman syndrome) on hemodialysis for 19 years: a case report

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is frequently associated with renal abnormalities, but there have been few reports about renal abnormalities in patients with hereditary TTP. In particular, little is known about the long-term prognosis of patients with childhood-onset congenital TTP.

CASE PRESENTATION

We report a Japanese patient with congenital TTP (Upshaw-Schulman syndrome) who was followed for 19 years after initiation of hemodialysis when he was 22 years old. At the age of 6 years, the first episode of purpura, thrombocytopenia, and proteinuria occurred without any precipitating cause. He underwent living-related donor kidney transplantation from his mother, but the graft failed after 5 months due to recurrence of TTP. Even after resection of the transplanted kidney and resumption of regular hemodialysis, TTP became refractory to infusion of fresh frozen plasma (FFP). Therefore, splenectomy was performed and his disease remained in remission for 10 years. However, TTP recurred at the age of 39 years. Plasma activity of ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type I domain 13) was less than 3%, while ADAMTS13 inhibitor was not detected (<0.5 Bethesda units/mL). The patient died suddenly after hemodialysis at the age of 41 years. Subsequent genetic analysis of this patient and his parents revealed two different heterozygous mutations of ADAMTS13, including a missense mutation in exon 26 (c.T3650C causing p.I1217T) inherited from his father and a missense mutation in exon 21 (c.G2723A causing p.C908Y) inherited from his mother. The former mutation has not been detected before in Japan, while the latter mutation is common in Japan. A retrospective review showed that serum C3 levels were consistently low while C4 levels were normal during follow-up, and C3 decreased much further during each episode of TTP.

CONCLUSION

Congenital TTP was diagnosed from the clinical, biochemical, and genetic findings. Infusion of FFP controlled each thrombotic episode, but the effect was limited and of short duration. Review of the complement profile in this patient suggested that a persistently low serum C3 level might be associated with refractory TTP and a worse renal prognosis.

Congenital thrombotic thrombocytopenic purpura associated with moyamoya syndrome in a 3-year-old girl: a case report

A 3-year-old girl who presented with anemia, thrombocytopenia, and recurrent strokes is described. The cerebral angiography revealed moyamoya vasculopathy. Her younger brother also had anemia and thrombocytopenia but no neurologic abnormalities. Both children had severe deficiency of ADAMTS13 (A Disintegrin And Metalloprotease with Thrombospondin like domain activity) confirming the diagnosis of congenital thrombotic thrombocytopenic purpura. The children responded well to regular fresh-frozen plasma infusions. This report expands the spectrum of hematologic diseases associated with moyamoya syndrome. Unexplained thrombocytopenia, especially in the presence of neurologic symptoms, should prompt an evaluation for ADAMTS13deficiency. The diagnosis has significant implications not only for therapy but also for genetic counseling.

Structure and proteolytic properties of ADAMTS13, a metalloprotease involved in the pathogenesis of thrombotic microangiopathies

ADAMTS13 is a 190-kDa zinc protease encoded by a gene located on chromosome 9q34. This protease specifically hydrolyzes von Willebrand factor (VWF) multimers, thus causing VWF size reduction. ADAMTS13 belongs to the A Disintegrin And Metalloprotease with ThromboSpondin type 1 repeats (ADAMTS) family, involved in proteolytic processing of many matrix proteins. ADAMTS13 consists of numerous domains, including a metalloprotease domain, a disintegrin domain, several thrombospondin type 1 (TSP1) repeats, a cysteine-rich domain, a spacer domain, and two CUB (Complement c1r/c1s, sea Urchin epidermal growth factor, and Bone morphogenetic protein) domains. ADAMTS13 cleaves a single peptide bond (Tyr(1605)-Met(1606)) in the central A2 domain of the VWF molecule. This proteolytic cleavage is essential to reduce the size of ultralarge VWF polymers, which, when exposed to high shear stress in the microcirculation, are prone to form platelets clumps, which cause severe syndromes called thrombotic microangiopathies (TMAs). In this chapter, we (a) discuss the current knowledge of structure-function aspects of ADAMTS13 and its involvement in the pathogenesis of TMAs, (b) address the ongoing controversies, and (c) indicate the direction of future investigations.

Natural history of Upshaw-Schulman syndrome based on ADAMTS13 gene analysis in Japan

Upshaw-Schulman syndrome (USS) is an extremely rare hereditary deficiency of ADAMTS13 activity, termed congenital TTP. The clinical signs are usually mild during childhood, often with isolated thrombocytopenia. But their symptoms become more evident when patients have infections or get pregnant. We identified 43 USS-patients in Japan, who ranged in age from early childhood to 79 years of age. Analysing the natural history of these USS patients based on ADAMTS13 gene mutations may help characterise their clinical phenotypes. Severe neonatal jaundice that requires exchange blood transfusion, a hallmark of USS, was found in 18 of 43 patients (42%). During childhood, 25 of 43 patients were correctly diagnosed with USS without gender disparity. These 25 patients were categorised as having 'the early-onset phenotype'. Between 15 and 45 years of age, 15 were correctly diagnosed, and, interestingly, they were all female. The remaining three patients were male and were diagnosed when they were older than 45 years of age, suggesting that they were 'the late-onset phenotype'. Two of these three males developed sudden overt TTP when they were 55 and 63 years old, respectively. These two men had two different homozygous ADAMTS13 gene mutations, p.R193W/p.R193W and p.C1024R/p.C1024R, respectively. Both of which were not discovered in the US or Western countries. In vitro expression studies showed that these two proteins were consistently secreted into the culture medium but to a lesser extent and with reduced activity compared to the wild-type protein. Our results indicate that 'the late-onset phenotype' of USS is formed with ethnic specificity.