Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), is an inherited disease with symptoms of stroke, hair loss, and low back pain. The disease is rare and has only been diagnosed in about 50 patients, mostly of Japanese descent but few of Chinese and Spanish descent. There is currently no cure for CARASIL.
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Signs and symptoms
Patients that present with CARASIL usually experience neurological abnormalities by their 20s or 30s and strokes upon reaching their 40s. About 50% of affected patients present with stroke, and most strokes experienced by patients are lacunar infarcts. Many patients experience some form of mood changes, personality disorders, and or dementia. Alopecia, also known as hair loss, usually presents beginning in adolescence. The presence of spondylosis deformans and the onset of low back pain via the breakdown of intervertebral discs is also usually present. CARASIL is a degenerative disease, and most patients live only 10 years past symptom onset.
Genetics
CARASIL is caused by a deletion or duplication of the HTRA1 gene and involves an autosomal recessive inheritance. HTRA1 is located on chromosome 10 and encodes an enzyme that regulates signaling by the TGF-β family of proteins. TGF-β plays an important role in cellular functions, specifically angiogenesis. Those affected with CARASIL display mutant proteins unable to suppress TGF-β activity. Increase in TGF-β1 has been seen in the tunica media of affected small arteries.
Diagnosis
CARASIL is diagnosed by MRI scans of the brain. Diffuse white matter changes (leukoencephalopathy) and multiple lacunar infarcts in basal ganglia of thalamus are usually determining factors seen on MRI scans of affected individuals. Further genetic testing can be used to confirm the presence of the disease.
Treatment
There is currently no treatment or cure for CARASIL. Most frequently, a combination of supportive care and medications to prevent the occurrence of stroke are recommended.