Objective: To better delineate the clinical spectrum and the natural history of COL4A1 mutations, a newly defined genetic cause of small vessel disease including the brain and retina.
Methods: Clinical and brain MRI follow-up study of a family with COL4A1 mutation.
Results: During a 7-year period, two affected members died from intracranial hemorrhage. Four other members had a COL4A1 mutation (age ranges 25 to 74 years). None reported stroke or retinal hemorrhage or hematuria and none had dementia according to Diagnostic and Statistical Manual of Mental Disorders-IV criteria. Follow-up brain MRI showed grade 3 diffuse leukoencephalopathy in three out of four patients. All had dilated perivascular spaces and three out of four had silent microbleeds mainly in the deep white matter. MRI signal abnormalities did not change in severity, number, or location between baseline and follow-up imaging.
Conclusions: COL4A1 mutation carriers have great diversity in the clinical expression of the disease within the same family. Some affected family members may remain asymptomatic during several years of follow-up and have no evidence of progression of vascular changes on brain MRI.