This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome is a genetic condition that causes blood vessels to become fragile. Signs and symptoms include muscle cramps, Raynaud phenomenon, kidney cysts, blood in the urine (typically not visible to the eye), leukoencephalopathy (a change in brain tissue that can be seen on MRI), arteries in the back of the eye that twist and turn abnormally, headaches, and supraventricular arrhythmia. These signs and symptoms do not often cause serious complications, however temporary vision loss due to bleeding in the back of the eye, minor ischemic stroke, and bleeding complications with blood thinner use has been described. While muscle cramps may begin in childhood, many of the other symptoms do not appear until later in life. HANAC syndrome is caused by mutations in the COL4A1 gene. It is passed through families in a autosomal dominant fashion.
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