Structural and functional analysis of retinal vasculature in HANAC syndrome with a novel intronic COL4A1 mutation.

PURPOSE: Mutations of the COL4A1 gene, a major structural protein of vessels, 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. METHODS: Clinical data from six affected individuals (43 to 72 years old) from a single family comprising 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. RESULTS: 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 patients had arterial hypertension, and three had kidney dysfunction, one of which under dialysis. By fundus examination, five had typical retinal arteriolar tortuosity with arteriolar loops. 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 in the two oldest patients. In three affected subjects, evaluation of the neurovascular coupling showed a higher flicker-induced vasodilation than a control population (6 % to 11 %; n < 5 %). CONCLUSIONS: Structural and dynamic analysis of retinal vessels in a HANAC family bearing a previously unreported intronic COL4 mutation was done. In addition to arteriolar tortuosity, we found reduced wall-to-lumen ratio, arteriolar irregularity and increased vasodilatory response to flicker light. These abnormalities were more marked in the oldest subjects. This abnormal flicker response affected also non-tortuous arteries, suggesting that microvascular dysfunction extends beyond tortuosity. Such explorations may help to better vascular dysfunction related to HANAC and hence better understand the mechanisms of end-organ damage.

Late Contralateral Recurrence of Unilateral Acute Idiopathic Maculopathy: Adaptive Optics Findings.

PURPOSE: To report a case of late contralateral recurrence of unilateral acute idiopathic maculopathy (UAIM) and its sequelae by using adaptive optics. METHODS: A 46-year-old woman positive for coxsackie virus presented with a typical UAIM, followed 3 years later by a recurrence in the fellow eye. At an early stage, spectral domain-OCT showed a localized loss of the inner segment/outer segment and cone outer segment tips lines, while flood-illumination adaptive optics displayed pigment clumpings and transient small hard exudates, associated with a persistent blurring of the cone mosaic. RESULTS: These findings support the hypothesis of an outer retinal blood-barrier breakdown, inducing a disruption limited to the outer segment of the photoreceptors, followed by a progressive though incomplete normalization of the cone mosaic characterized by a persistent misalignment of outer segment tips. CONCLUSION: This would explain the acute clinical presentation of UAIM, followed by a spontaneous, partial, recovery, with a relative scotoma remaining over time.