SNP Shot: Genomic Insights

Psoriatic arthritis is a type of arthritis characterized by joint inflammation, typically occurring alongside the skin condition psoriasis. Psoriasis is a long-term inflammatory condition marked by red, irritated skin patches often covered with flaky, white scales. Individuals with psoriasis may also experience changes in their fingernails and toenails, such as pitting, ridges, crumbling, or separation from the nail bed.

Signs and symptoms of psoriatic arthritis include stiff, painful joints accompanied by redness, warmth, and swelling in the surrounding tissues. When the hands and feet are involved, this can lead to a "sausage-like" swelling of the fingers or toes, a condition known as dactylitis.

In the majority of psoriatic arthritis cases, psoriasis appears before the onset of joint problems. Psoriasis often starts during adolescence or early adulthood, while psoriatic arthritis typically manifests between the ages of 30 and 50. However, both conditions can occur at any age. In some instances, psoriatic arthritis can develop without any noticeable skin changes.

Diagnosing psoriatic arthritis can be challenging, especially when skin symptoms are minimal or absent, as it can resemble other forms of arthritis. Nail changes and dactylitis are distinctive features of psoriatic arthritis, though they are not always present.

Psoriatic arthritis is classified into five subtypes: distal interphalangeal predominant, asymmetric oligoarticular, symmetric polyarthritis, spondylitis, and arthritis mutilans.

The distal interphalangeal predominant type primarily affects the joints at the ends of the fingers and toes, specifically those closest to the nails. Nail changes are particularly common in this form of psoriatic arthritis.

The asymmetric oligoarticular and symmetric polyarthritis types are the most frequently observed forms of psoriatic arthritis. Asymmetric oligoarticular involves different joints on each side of the body, while symmetric polyarthritis affects the same joints on both sides. These forms can affect any joint in the body, with symptoms ranging from mild to severe.

Some individuals with psoriatic arthritis primarily experience joint involvement in the form of spondylitis, which is inflammation of the joints between the vertebrae in the spine. This form of the disorder causes pain and stiffness in the back or neck, often limiting movement. Joints in the arms, legs, hands, and feet may also be affected.

Arthritis mutilans is the most severe, but also the rarest, type of psoriatic arthritis, affecting less than 5% of individuals with the condition. It involves severe inflammation that damages the joints in the hands and feet, leading to deformation and impaired movement. Bone loss (osteolysis) at the joints can result in shortening (telescoping) of the fingers and toes. Pain in the neck and back may also occur.

Inheritance:

The inheritance pattern of this condition is currently unknown. Approximately 40% of affected individuals have at least one close family member with either psoriasis or psoriatic arthritis.