SNP Shot: Genomic Insights

Progressive pseudorheumatoid dysplasia (PPRD) is a progressive joint disorder. The hallmark of this condition is the deterioration (degeneration) of the articular cartilage, the protective tissue between bones in joints. This cartilage breakdown leads to joint pain, stiffness, and other characteristic features of PPRD.

PPRD typically manifests in early childhood, usually between the ages of 3 and 8. Initial symptoms commonly include an unusual gait, weakness and tiredness during physical activity, and joint stiffness, particularly in the fingers and knees. As the condition progresses, individuals may develop permanently bent fingers (camptodactyly), enlarged finger and knee joints (frequently misidentified as swelling), and a narrowing of the space between bones in the hip and knee joints. By adolescence, hip pain is a frequent complaint. Affected individuals also exhibit flattened and abnormally shaped (beaked) vertebrae (platyspondyly), resulting in an exaggerated curvature of the upper back (kyphosis) and a shortened trunk. While individuals with PPRD are of normal length at birth, they typically experience reduced height compared to their peers by adulthood. Adult patients often display abnormal calcium deposits around the elbow, knee, and hip joints, along with restricted movement in all joints, including the spine.

PPRD is frequently confused with juvenile rheumatoid arthritis, another joint condition affecting young individuals. However, unlike juvenile rheumatoid arthritis, which involves inflammation of the joints, PPRD does not.

Inheritance:

PPRD follows an autosomal recessive inheritance pattern. This means that an individual must inherit two copies of the mutated gene (one from each parent) to develop the condition. Both parents are carriers of one copy of the mutated gene but usually do not exhibit any signs or symptoms of PPRD themselves.