Impact of RNF213 c.14576G>A Variant on the Development of Direct and Indirect Revascularization in Pediatric Moyamoya Disease.

Background: Superficial temporal artery (direct) and encephalomyosynangiosis (indirect) revascularization may develop after combined bypass surgery in pediatric patients with moyamoya disease (MMD). However, arterial development varies widely among patients, and the underlying mechanisms remain unknown. Objectives: We evaluated the relationship between the development of donor arteries after bypass surgery in pediatric patients with MMD and the MMD-susceptibility gene variant c.14576G>A of ring finger protein (RNF) 213. Methods: The data of pediatric patients with MMD (age <16 years at the time of surgery) treated with combined bypass surgery between September 2013 and April 2019 were consecutively analyzed. Quantitative measurements of the superficial temporal artery (STA), deep temporal artery (DTA), and middle meningeal artery (MMA) diameters with magnetic resonance angiography (MRA) source imaging were performed preoperatively and at 6–12 months postoperatively. The postoperative caliber change ratios (CCRs) were calculated. The relationship between CCRs and RNF213 c.14576G>A status was examined. Results: Forty-eight hemispheres from 28 pediatric patients with MMD were examined. Three hemispheres belonged to patients with the AA genotype; 33 to patients with the AG genotype (AA/AG group); and 12 to patients with the GG genotype (GG group; wild type). The CCRs for the DTA were significantly higher in patients with RNF213 variant (AA/AG group; 2.5 ± 0.1) than in the GG group (2.0 ± 0.2) (p = 0.03), whereas the CCRs for the STA were significantly higher in the GG (1.6 ± 0.1) than in the AA/AG group (1.3 ± 0.6) (p = 0.02). There was no significant difference in the CCRs for the MMA and basilar artery between the groups. Other factors, including sex, age, and MRA grading, were not associated with the development of specific bypass development. Conclusions: The extent of collateral development associated with direct or indirect bypass was found to differ between the genotypes of the RNF213 c.14576G>A associated with pediatric MMD. This genetic variant correlates with the development of the disease and affects revascularization after bypass surgery in pediatric patients with MMD. [ABSTRACT FROM AUTHOR]