Moya-Moya related to RNF gene: case report and clinical implications

*Correspondence: [e-mail].

Abstract

Case Presentation: Japanese descent boy, 9yo, started transient ischemic attacks, characterized by intermittent loss of strength for about 3 months, until he had an episode of stroke. On admission, the MRI showed, in DWI, restriction on the left temporo-parietal cortico-subcortical region. MRI angiography showed narrowing of the middle cerebral arteries and collateral circulation bilateral. Genetic testing was chosen due to the family history for Moyamoya Disease (MMD). The Genetic Panel revealed a mutation on gene RNF213 [c.14429G>A (p.Arg4810Lys)], an autosomal dominant variant, known pathogenic related to MMD. The patient was submitted to surgical intervention, with the performance encephalo-duro-arterio-myo-synangiosis (EDAMS) on the left side. A month after surgery, the patient develops a new stroke with contralateral motor deficit, anarthria, dysphagia and pseudobulbar syndrome. After this new event, he underwent over again an EDAMS surgery to the arteries on the right side.

Discussion: MMD is characterized by progressive stenosis of large intracranial arteries, mainly in distal internal carotid artery, that could cause transient ischemic attacks, strokes and intracranial hemorrhage. Children under 10 years old account for 50% of cases of MMD. Polymorphism (R4810K) in the Ring Finger Protein 213 (RNF213) gene, at chromosome 17q25.3 was identified as a susceptibility gene for MMD among the East Asian population. In Japanese studies this variant was identified in 95% of patients with familial MMD and 80% with sporadic MMD. The homozygous c.14429G>A (p.R4810K) variant was related to an early-onset and a severe symptomatic manifestation form of MMD in Japanese and Korean patients. Special attention should be given to these cases, as this genotypic variant may be a useful biomarker to early diagnosis and revascularization treatment.

Final Comments: The RNF213 gene related MMD demands an early surgical intervention, to prevent future complications and to provide a better prognosis. In an era of greater interest and greater availability of genetic testing, we must consider this data to provide individualized treatment.

Publication History

Article published online:
12 May 2025