Synergistic Interaction of Thyroid Autoantibodies and Ring Finger Protein 213 Variant in Moyamoya Disease

Recently, thyroid autoantibodies were found to be associated with moyamoya disease (MMD). The ring finger protein 213 (RNF213) p.R4810K variant represents the most important susceptibility genotype of this disease, but its relationship with thyroid autoantibodies remains to be elucidated. Thus, in this study, we aimed to evaluate the clinical relevance of thyroid autoantibodies in each RNF213 genotype in patients with MMD. Included in this study were patients with MMD without a thyroid disease history and in euthyroid status; they were then classified into the mutated or nonmutated based on the RNF213 p.R4810K genotype and positive or negative based on thyroid autoantibody (thyroperoxidase and thyroglobulin) levels. Clinical data of each group were thereafter evaluated. Among the 209 patients, the mutated RNF213 p.R4810K variant and positive thyroid autoantibodies were detected in 155 and 41 patients, respectively. Positive thyroid autoantibodies were found to be more common in the nonmutated patients than in the mutated patients (31.5% vs. 15.5%; P = 0.011). In the mutated patients, as compared to autoantibody-negative patients, autoantibody-positive patients were determined to be more likely to have advanced disease with posterior cerebral artery involvement (54.2% vs. 29.0%; P = 0.017), white matter infarction (58.3% vs. 37.6%; P = 0.046), and a higher modified Rankin Scale at last visit (16.7% vs. 3.1%; P = 0.021). These results suggest that thyroid autoantibodies can act as an immunity inducer in patients with MMD lacking the susceptibility gene RNF213 p.R4810K variant. Moreover, the simultaneous presence of thyroid autoantibodies and the variant seems to aggravate the disease, which indicates synergy between thyroid autoantibodies and the variant.

A Case of Cerebral Hyperperfusion Syndrome during Treatment of Transient Cerebral Vasospasm Following Carotid Artery Stenting

Objective

We report a case in which transient cerebral vasospasm after carotid artery stenting (CAS) was effectively treated using arterial and intravenous infusion of fasudil hydrochloride, but cerebral hyperperfusion syndrome (CHS) developed during subsequent treatment.

Case Presentation

The patient was a 79-year-old man who underwent right CAS to treat symptomatic right carotid artery stenosis. After the procedure, the patient developed left paresis and unilateral spatial neglect. The following day, he developed diffuse cerebral vasospasm in the right middle cerebral artery that improved immediately upon arterial infusion of fasudil hydrochloride. Intravenous infusion of fasudil hydrochloride was then started, but CHS with epileptic seizures developed after 1 day of treatment. After 23 days of medical treatment, the condition of the patient improved to mild hemiparesis.

Conclusion

The present case suggests that transient cerebral vasospasm after CAS may turn into CHS during treatment and that continuous monitoring for cerebral perfusion is important.

Absence of the RNF213 p.R4810K variant may indicate a severe form of pediatric moyamoya disease in Japanese patients

OBJECTIVE

The authors' objective was to investigate the influence of the RNF213 p.R4810K variant on the clinical presentation and outcomes of Japanese pediatric patients with moyamoya disease.

METHODS

A total of 129 Japanese patients with pediatric-onset moyamoya disease (onset age ≤ 15 years) who visited the authors' department from 2012 to 2020 participated in this study. After RNF213 p.R4810K genotyping of each patient was performed, the relationship between genotype and clinical presentation or outcomes, including onset age, initial presentation, surgical outcomes, and subsequent cerebrovascular events, was evaluated. Patients without the p.R4810K variant were tested for RNF213 variants other than p.R4810K. The authors especially focused on the results of patients who presented with moyamoya disease at younger than 1 year of age (infantile onset).

RESULTS

Compared with the patients with heterozygous variants, patients without the p.R4810K variant were younger at onset (7.1 ± 3.7 vs 4.4 ± 0.9 years), and all 4 patients with infantile onset lacked the p.R4810K variant. A greater proportion of patients without the p.R4810K variant presented with infarction than patients with the heterozygous variant (24.0% vs 7.6%) and a decreased proportion presented with transient ischemic attack (36.0% vs 71.7%). No significant correlation was observed between p.R4810K genotype and clinical outcomes, including surgical outcomes and subsequent cerebrovascular events; however, a decreased proportion of patients without the p.R4810K variant had good surgical outcomes compared with that of patients with the heterozygous variant (76.5% vs 92.2%). Among the 25 patients without the p.R4810K variant, 8 rare variants other than p.R4810K were identified. Three of 4 patients with infantile onset had RNF213 variants other than p.R4810K, which had a more severe functional effect on this gene than p.R4810K.

CONCLUSIONS

Absence of the RNF213 p.R4810K variant may be a novel biomarker for identification of a severe form of pediatric moyamoya disease.