Beschreibung:
<jats:title>Abstract</jats:title><jats:sec><jats:label /><jats:p><jats:bold>Purpose:</jats:bold> Mutations of the COL4A1 gene may cause hereditary angiopathy with nephropathy, aneurysms and muscle cramps (HANAC) syndrome. The vascular structure and function of patients with HANAC is poorly known. Here, we report a family with HANAC syndrome associated to a previously unreported mutation in COL4A1. The structure and function of retinal vessels were detailed by adaptive optics ophthalmoscopy (AOO) and optical coherence tomography (OCT) angiography.</jats:p><jats:p><jats:bold>Methods:</jats:bold> Clinical data from six affected individuals from a single family over two generations were collected. Imaging charts including conventional fundus imaging, OCT‐angiography and AOO in static and dynamic (flicker) mode were reviewed. DNA sequencing was done in the proband.</jats:p><jats:p><jats:bold>Results:</jats:bold> DNA sequencing of the proband revealed a heterozygous deletion of COL4A1 (NM_001845) at position 1120 in the intron 20 resulting in the loss of splicing donor site for exon 20 (c.1120 + 2_1120 + 8del heterozygote). Four had arterial hypertension, and three had kidney dysfunction, one of which under dialysis. Examination of retinal vessels showed that all patients had retinal arteriolar tortuosity which peaked in precapillary arterioles but spared capillaries and veins. Wall‐to‐lumen ratio of arteries was within normal limits, that is, lower than expected for hypertensive patients. Several foci of arteriolar irregularities were noted I the oldest patients. In three affected subjects, evaluation of the neurovascular coupling showed a high flicker‐induced vasodilation (from 6% to 10.8%; <jats:italic>n</jats:italic> < 5%).</jats:p><jats:p><jats:bold>Conclusions:</jats:bold> Structural and dynamic analysis of retinal vessels in a HANAC family bearing a novel intronic COL4 mutation showed reduced parietal thickness, arteriolar irregularity and increased dilatory response to flicker light. This affected as well non tortuous arteries, suggesting that HANAC causes diffuse microvascular dysfunction. Our findings may help to better understand end‐organ damage related to HANAC.</jats:p></jats:sec>