COL4A1/COL4A2 mutations cause a multi-systemic disorder encompassing cerebrovascular disease, including intracerebral haemorrhage (ICH), as well as eye and renal defects (4–7) including HANAC syndrome (8,9). This evidence concerns the gene COL4A1 and autosomal dominant familial hematuria-retinal arteriolar tortuosity-contractures syndrome.