A 34-year-old Thai woman developed acute left hemiparesis with dysarthria from subcortical infarction of the right MCA territory eighteen months after being diagnosed with Noonan syndrome, diabetes mellitus, dyslipidaemia, and hypertension. Further investigations suggested atherosclerosis as a cause. Modifying her risk factors was difficult, partly because of limited adherence. Three years later, she had another attack of ischaemic stroke in the same area. Unlike the three previously reported cases, the causation of strokes in this patient appeared to be a more 'complex' interaction between genetic defect and environment including possible subtle arterial abnormalities, metabolic risk factors, and mental insufficiency.