SNP Shot: Genomic Insights

Blau syndrome is an inflammatory disease primarily impacting the skin, joints, and eyes. The first signs and symptoms typically appear in childhood, usually before the age of four.

Granulomatous dermatitis, a type of skin inflammation, is often the initial indicator of Blau syndrome. This condition leads to a persistent rash that may be scaly or feature hard lumps (nodules) palpable beneath the skin. The rash commonly appears on the trunk, arms, and legs.

Arthritis is another common characteristic of Blau syndrome. Individuals affected experience inflammation of the joint lining (synovium), known as synovitis. Synovitis causes swelling and pain in the joints. It typically begins in the joints of the hands, feet, wrists, and ankles. As the disease progresses, it can involve more joints, restricting movement by limiting the range of motion. In Blau syndrome, both joints and tendons can become inflamed, resulting in tenosynovitis.

Uveitis, inflammation of the middle layer of the eye (the uvea), occurs in most individuals with Blau syndrome. The uvea includes the iris (colored part of the eye) and related tissues beneath the white part of the eye (sclera). Uveitis can cause eye irritation, pain, increased sensitivity to light (photophobia), and blurred vision. Other eye structures, such as the conjunctiva (outermost protective layer), tear glands, retina (light-sensitive tissue at the back of the eye), and optic nerve (nerve connecting the eye to the brain), can also become inflamed. Although some individuals with Blau syndrome may have normal vision, inflammation of these structures can lead to severe vision loss or blindness.

Some individuals with Blau syndrome develop kidney inflammation (nephritis), which can lead to kidney disease. Calcium deposits in the kidneys (nephrocalcinosis) and chronic kidney failure are also common. Inflammation of blood vessels (vasculitis) can cause scarring and tissue death, obstructing blood flow to tissues and organs.

Less frequently, Blau syndrome can affect other parts of the body, including the liver, spleen, lymph nodes, brain, blood vessels, lungs, and heart. Inflammation in these areas can impair organ function and cause life-threatening complications. In rare cases, affected individuals may experience nerve dysfunction (neuropathy), fever episodes, or high blood pressure in the blood vessels carrying blood from the heart to the lungs (pulmonary hypertension).

Inheritance:

Blau syndrome follows an autosomal dominant inheritance pattern, meaning only one copy of the mutated gene in each cell is needed to cause the condition. Most affected individuals inherit the gene from a parent with the condition.

In some instances, individuals exhibiting the typical features of Blau syndrome have no family history of the disorder. Some researchers suggest that these individuals may have a non-inherited form of the disease referred to as early-onset sarcoidosis.