COL4A1 and X-linked adrenoleukodystrophy: In a 2015 European cohort study of 154 patients, cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) was the most common diagnosis (33%), followed by vanishing white matter disease (VWMD), X-linked adrenoleukodystrophy (X-ALD), and COL4A1-related disorders (5).