Chromosomal rearrangements of 6p25.3 and Moyamoya syndrome: a non-incidental association

Objective: To present a case carrying a chromosomal rearrangement of the 6p25.3 locus and diagnosed with Moyamoya syndrome. Methods: A Caucasian 4 years-and-9-months-old girl was admitted to a peripheral hospital for vomiting and acute left hemiparesis, followed by left arm clonic seizures, aphasia and confusion. Phenytoin stopped the crisis, but hemiparesis persisted. EEG documented widespread slow waves, mainly on the right hemisphere. Computed tomography (third day) showed hypodensity of the entire right hemisphere. Past history was characterized by prematurity (born at 32 g.w.), cardiac defects (atrial septal defect, patent ductus arteriosus), surgically corrected at 3 years old. High resolution karyotype showed this rearrangement: 46, XX, der(6)dup(6) (p24p23)del(6)(p25). Cognitive level was borderline. On day 4 the girl was transferred to our Child Neurology Unit where she underwent a complete workup. Results: Echocardiogram: normal; carotid doppler ultrasound: bilateral stenosis of internal carotid arteries; brain magnetic resonance imaging (MRI): ischemic areas in territories supplied by right middle and anterior cerebral arteries; brain angio-MRI: bilateral multiple stenosis of anterior and posterior cerebral arteries and collateral circulation consistent with Moyamoya syndrome. Therefore, after a digital angiography, the patient underwent an encephalo-duro-arterial-myo-sinangiosis. The post-operative period was uneventful. Conclusion: Moyamoya syndrome is known to be associated to some genetic conditions (such as Neurofibromatosis type 1, Alagille syndrome and Trisomy 21). To date, only one pediatric case with Moyamoya syndrome and chromosomal rearrangement of 6p25.3 has been reported, similar to our patient. Therefore, all patients presenting with a chromosomal rearrangement involving the 6p25.3 locus should be studied with brain angio-MRI; moreover this genetic region should be investigated to identify possible disease-specific genes for Moyamoya syndrome.