Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps syndrome

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.

In order to know how HANAC syndrome is affecting you, your doctor may recommend that you undergo a series of imaging tests of the brain and kidney, an eye exam, and blood tests (e.g., serum CK concentration).^[1] While there is not a targeted treatment for HANAC syndrome, treatments are available to manage its signs and symptoms, such as drugs to reduce high blood pressure, manage headaches, and treat arrhythmia. People with HANAC syndrome may be regularly monitored (e.g., once a year) for signs and symptoms.^[1] In order to reduce the risk for health complications, your doctor may advise you to avoid smoking, activities that can cause head trauma, and blood thinners (anticoagulants).^[1]

We recommend that you speak with your primary healthcare provider. In addition, you may wish to discuss your concerns with a genetics professional. Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference at http://ghr.nlm.nih.gov/handbook/consult. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:  

• The National Society of Genetic Counselors provides a searchable directory of US and international genetic counseling services.
• The American College of Medical Genetics has a searchable database of US genetics clinics.
• The University of Kansas Medical Center provides a list of US and international genetic centers, clinics, and departments.
• The American Society of Human Genetics maintains a database of its members, which includes individuals who live outside of the United States. Visit the link to obtain a list of the geneticists in your country, some of whom may be researchers that do not provide medical care.