Introduction
Osteoarthritis is the most common joint disease. Mutations in the gene encoding type II collagen affecting cartilage and bone and causing early-onset OA associated syndromic skeletal phenotypes. The objective of this case report is to evaluate an approach to the clinical, radiographic, and molecular diagnosis of an COL2A1 gene mutation in a young woman presenting with non-syndromic, early-onset osteoarthritis.
Case report
A 29-year-old woman presented to the hospital with both hip and knee pain. The patient’s father and 33-year-old sister have arthritis. She had a history of taking anti-inflammatory analgesic. Beginning at age 12 years, she experienced the development of hip and knee joint stiffness. From the age of 18, she has presented pain in her hip and knees, with limitation of motion in back and shoulders.
This patient was not dysmorphic, was of average stature with a normal upper: lower segment ratio, and had normal vision and hearing. Clinical examination revealed limitation of motion of the bilateral hip and knees as flexion contracture. Radiographs showed osteoarthritis in hip, knees, ankles, hands, feet and shoulders with multiple intraarticular loose bodies. A whole body bone scan revealed increased radioactive uptakes in the whole spines, both hip joints and both knee joints. The results of other investigations performed include HLA–B27 negativity, rheumatoid factor negativity, normal parathyroid hormone levels, ALP level of 15.80㎍/L and a vitamin D level of 18.40 ng/mL. The diagnosis was confirmed by identifying a mutation in the COL2A1 gene that is involved in type II collagen fibrillogenesis. COL2A1 mutation analysis revealed a Gly275Cys substitution.
Discussion
Mutations in the gene encoding type II collagen (COL2A1) give rise to a spectrum of phenotypes predominantly affecting cartilage and bone. We reported the COL2A1 mutations in an individual presenting with early-onset polyarticular arthritis without obvious syndromic features. The importance of finding a COL2A1 mutation in such patients lies in the subsequent ability to accurately assess recurrence risks, offer early diagnosis, and provide information regarding the natural history of the condition. In addition, understanding genetic determinism involved in OA pathogenesis will contribute to better patient diagnosis, management, and therapy.
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