[1] The syndrome has a number of possible symptoms and can, more rarely, affect the skin, bones, kidneys, muscles, and gastrointestinal tract.

[2][3] In the retina, the syndrome causes retinocephalic vascular malformations that tend to be present with intracranial hemorrhage and lead to decreased visual acuity, proptosis, pupillary defects, optic atrophy, congestion of bulbar conjunctiva, and visual field defects.

[5] The facial features caused by the syndrome vary from slight discoloration to extensive nevi and angiomas of the skin.

The second category, more severe than the first, is when the patient's malformation is missing a connecting capillary between an artery and a vein; without it, edema, hemorrhage, and visual impairment can result.

Category three refers to malformations so severe that their dilated vessels no longer distinguish between artery and vein, and the patient has a significantly increased risk of vision loss.

[3] Since the retinal lesions categorized vary from large vascular malformations that affect a majority of the retina to malformations that are barely visible, the lesions can cause a wide range of symptoms, including decrease in visual sharpness, proptosis, pupillary defects, optic nerve degeneration, and visual field defects.

[7] Central nervous system (CNS) symptoms of Bonnet–Dechaume–Blanc syndrome are highly dependent on the locations and sizes of cerebral AVMs.

The syndrome is a congenital disorder that begins to develop around the seventh week of gestation when the maturation of retinal mesenchymal cells do not grow properly.

[3][7][9] The abnormal development of vascular tissue leads to arteriovenous malformations, which affect both visual and cerebral structures.

MRI, CT, and cerebral angiography may all be used to investigate the extent and location of any vascular lesions affecting the brain.

[2][5] The treatment for Bonnet–Dechaume–Blanc syndrome is controversial due to a lack of consensus on the different therapeutic procedures for treating arteriovenous malformations.