CADASIL, CARASIL, collagen type IV mutations (including PADMAL), retinal vasculopathy with cerebral leukodystrophy, Fabry disease, hereditary cerebral hemorrhage with amyloidosis, and forkhead box C1 mutations are described in terms of genetics, pathology, clinical manifestation, imaging, and diagnosis.
Several COL4A1 mutations affecting a conformational domain containing integrin-binding sites are responsible for the systemic syndrome of hereditary angiopathy, nephropathy, aneurysms, and cramps (HANAC).
Missense mutations of COL4A1 that encode the CB3 [IV] segment of the triple helical domain (exons 24 and 25) are associated with HANAC syndrome (hereditary angiopathy, nephropathy, aneurysms and cramps).
Mutations in COL4A1, encoding one of the six collagen type IV proteins, cover a wide spectrum of autosomal dominant overlapping phenotypes including porencephaly, small-vessel disease and hemorrhagic stroke, leukoencephalopathy, hereditary angiopathy with nephropathy, aneurysms and muscle cramp (HANAC) syndrome, and Walker-Warburg syndrome.
COL4A1-associated disorders encompass a wide range of hereditary vasculopathy, including porencephaly and HANAC (adult-onset hemorrhagic stroke with cerebral aneurysm and retinal arterial tortuosity, renal cysts, and thenar muscle cramp).
Interestingly, the COL4A1p.Gly510Arg mutation has been previously identified in a family with HANAC (Hereditary Angiopathy with Nephropathy, Aneurysm and Cramps), a multisystemic disease featuring retinal arteriolar tortuosity.
Recently, COL4A1 mutations have been reported in porencephaly and other cerebral vascular diseases, often associated with ocular, renal, and muscular features.
We have previously reported three COL4A1 mutations associated with a systemic phenotype that we called HANAC (Hereditary Angiopathy, Nephropathy, Aneurysms, and Cramps).
COL4A1 is a further cause of familial vasculopathy and may present with stroke, ischemic as well as hemorrhagic, in adult life and with radiological features of leukoaraiosis and microbleeds.