Letter to the Editor. Influence of rare RNF213 variants other than p.R4810K on the clinical outcomes of moyamoya disease
Shunsuke Nomura, Akitsugu Kawashima, Hiroyuki Akagawa, and Takakazu Kawamata
Using endothelial nitric oxide synthase gene polymorphisms to identify intracranial aneurysms more prone to rupture in Japanese patients
Boris Krischek, Hidetoshi Kasuya, Hiroyuki Akagawa, Atsushi Tajima, Akira Narita, Hideaki Onda, Tomokatsu Hori, and Ituro Inoue
Recent investigators found that the presence of three tandem polymorphisms of the endothelial nitric oxide synthase (eNOS) gene—promoter single nucleotide polymorphism (SNP) T-786C, intron-4 27-bp variable number of tandem repeats, and the G894T SNP in exon 7—was indicative of intracranial aneurysms more prone to rupture in a Caucasian patient sample. In the present study, the authors sought to determine whether the presence of these eNOS polymorphisms could indicate which Japanese patients with aneurysms were more endangered by a subarachnoid hemorrhage (SAH).
The three eNOSpolymorphisms were genotyped in 297 patients with ruptured aneurysms (RAs), 108 patients with unruptured aneurysms (UAs), and 176 healthy volunteers by using polymerase chain reaction.
The distribution of the variant alleles did not differ significantly (p > 0.05) between the RA group and the UA group. The frequency of the corresponding genotypes between the two groups and a haplotype analysis did not show any significant differences. Further comparisons of the RA and UA groups with the control group did not yield any significant allele or genotype frequency differences.
These data show that the examined set of eNOS polymorphisms were not indicative of which Japanese patients with intracranial aneurysms would suffer an SAH. The presence of eNOS polymorphisms is not useful in identifying intracranial aneurysms that are more prone to rupture in a Japanese patient sample.
Absence of the RNF213 p.R4810K variant may indicate a severe form of pediatric moyamoya disease in Japanese patients
Shoko Hara, Maki Mukawa, Hiroyuki Akagawa, Thiparpa Thamamongood, Motoki Inaji, Yoji Tanaka, Taketoshi Maehara, Hidetoshi Kasuya, and Tadashi Nariai
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.
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).
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.
Absence of the RNF213 p.R4810K variant may be a novel biomarker for identification of a severe form of pediatric moyamoya disease.
Influence of endothelial nitric oxide synthase T-786C single nucleotide polymorphism on aneurysm size
Hiroyuki Akagawa, Hidetoshi Kasuya, Hideaki Onda, Taku Yoneyama, Atsushi Sasahara, Chul-Jin Kim, Jung-Chung Lee, Tae-Ki Yang, Tomokatsu Hori, and Ituro Inoue
Object. Among patients with aneurysms, those with heterozygous (T/C) endothelial nitric oxide synthase (eNOS) T-786C single nucleotide polymorphism (SNP), a mutation reducing endothelial nitric oxide synthesis, are reported to have larger ruptured intracranial aneurysms (IAs) than those with homozygous (C/C or T/T) genotype. The authors tested patients harboring aneurysms for eNOS T-786C SNP in two populations—Japanese and Korean.
Methods. The eNOS T-786C SNP was genotyped through direct sequencing in genomic DNA obtained from 336 Japanese and 191 Korean patients with IAs and 214 Japanese and 191 Korean control volunteers. Differences in genotype frequencies among the various aneurysm sizes were evaluated using the Fisher exact test.
There was no significant difference in heterozygous (T/C) eNOS T-786C SNP between aneurysms 5 mm or smaller and those from 6 to 9 mm, and between lesions 5 mm or smaller and those 10 mm or larger in 336 Japanese patients harboring aneurysms—220 with ruptured and 116 with unruptured lesions—and in 191 Korean patients with ruptured aneurysms.
Conclusion. The eNOS T-786C SNP genotype does not influence the size of aneurysms.