Rare RNF213 variant in adolescent with moyamoya disease.

Introduction: Moyamoya disease is a progressive steno-occlusive disease of the major intracranial arteries. Affected individuals are at risk for intracranial hemorrhagic or ischemic stroke, cognitive impairment, and developmental delays. Several susceptibility genes have been identified. The p.R4810K variant in the RNF213 gene has been identified in 95% of patients with familial moyamoya disease.

Case Report: We present the case of a 15-year-old adolescent girl who presented with chief complaints of dysgraphia, lack of coordination in the right hand, with two months of evolution. Cerebral magnetic resonance imaging revealed several ischemic lesions with different rates of evolution and magnetic resonance angiography showed multiple subocclusive stenoses. In the study of the sequences of the coding regions and intronic flanking regions (±8 bp) of the RNF213 gene, the variant c.12185G>A, p.(Arg4062Gln) was detected in heterozygosity in the RNF213 gene. This result indicates that the patient is heterozygous for the c.12185G>A, p.(Arg4062Gln) variant in the RNF213 gene. The detected variant has already been reported in the literature as a founder variant in the Asian population, associated with moyamoya syndrome. This variant is described in ClinVar as a variant of unknown clinical significance? Furthermore, it is not described in population databases (dbSNP, ESP, gnomAD).

Conclusion: To our knowledge, the p.(Arg406262Gln) variant has been reported in three Japanese moyamoya disease patients and one European. Therefore, our patient was the second European moyamoya disease patient with this variant identified.