Calcification of Joints and Arteries (CALJA) Is a Rare Cause of Arthritis and Lower Limb Ischemia: Case Report and Literature Review

Abstract

Calcification of Joints and Arteries (CALJA) is a rare disease that leads to chronic arthritis and lower limb claudication due to hydroxyapatite crystal deposition. The disease is caused by mutations in the 5-nucleotidase (NT5E) gene, which is responsible for pyrophosphate metabolism. Only 23 cases have been described so far. In this case report, we describe a new case of CALJA and provide a literature review. A 65-year-old woman was referred to the Rheumatology Unit with the diagnosis of seronegative oligo-arthritis. She complained of lower limb claudication, which was becoming progressively worse. Doppler ultrasound revealed bilateral obliteration of the popliteal and femoral arteries, and X-rays of the knees, hands, and feet showed extensive periarticular calcific deposits. The results of the NT5E gene analysis were positive for an inactivating variant, leading to the diagnosis of CALJA. The clinical features of CALJA are caused by hydroxyapatite crystal deposition at the periarticular and vascular levels due to abnormalities of pyrophosphate metabolism. Currently, no specific treatment is available, although a trial on the use of etidronate is ongoing. Patients with CALJA are often treated with immunosuppressant agents in the suspect of inflammatory rheumatologic diseases. Our case is the first in which clinical symptoms and a steady increase of inflammatory markers improved only after colchicine therapy initiation. It is crucial for the rheumatologist to recognize the features CALJA and keep it in mind in the differential diagnosis of patients with lower limb arterial insufficiency and arthritis or early osteoarthritis with joint calcification.