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Progressive pseudorheumatoid dysplasia
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Progressive pseudorheumatoid dysplasia

Progressive pseudorheumatoid dysplasia (PPRD) is a joint disease that worsens over time, characterized by the degeneration of articular cartilage, leading to pain, stiffness, and skeletal abnormalities typically beginning in childhood due to mutations in the CCN6 gene.

Overview

Progressive pseudorheumatoid dysplasia (PPRD) is a joint disease that worsens over time. This condition is characterized by breakdown (degeneration) of the cartilage between bones (articular cartilage). This cartilage covers and protects the ends of bones, and its degeneration leads to pain and stiffness in the joints and other features of PPRD.

PPRD usually begins in childhood, between ages 3 and 8. The first indications are usually an abnormal walking pattern, weakness and fatigue when active, and stiffness in the joints in the fingers and in the knees. Other signs and symptoms that develop over time include permanently bent fingers (camptodactyly), enlarged finger and knee joints (often mistaken as swelling), and a reduced amount of space between the bones at the hip and knee joints. Hip pain is a common problem by adolescence. Affected individuals have flattened bones in the spine (platyspondyly) that are abnormally shaped (beaked), which leads to an abnormal front-to-back curvature of the spine (kyphoscoliosis) and a short torso. At birth, people with PPRD are of normal length, but by adulthood, they are usually shorter than their peers. Affected adults also have abnormal deposits of calcium around the elbow, knee, and hip joints and limited movement in all joints, including those of the spine.

PPRD is often mistaken for another joint disorder that affects young people called juvenile rheumatoid arthritis. However, the joint problems in juvenile rheumatoid arthritis are associated with inflammation, while those in PPRD are not.

Frequency

PPRD has been estimated to occur in approximately 1 per million people in the United Kingdom. The condition is thought to be more common in Turkey and the Middle East, although its prevalence in these regions is unknown. The condition in all regions is likely underdiagnosed because it is often misdiagnosed as juvenile rheumatoid arthritis.

Causes & Risk Factors

PPRD is caused by mutations in the CCN6 gene. The function of the protein produced from this gene is not well understood, although it is thought to play a role in bone growth and cartilage maintenance. The CCN6 protein is made in cells called chondrocytes, which produce and maintain cartilage. This protein is associated with the production of certain proteins that make up cartilage, but its role in their production is unclear. CCN6 may also help control signaling pathways involved in the development of cartilage and bone and may help regulate the breakdown of cartilage components.

CCN6 gene mutations lead to an altered protein that may not function. Loss of CCN6 protein function likely disrupts normal cartilage maintenance and bone growth, leading to the cartilage degeneration and joint problems that occur in PPRD.

Inheritance

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Other Names

  • Progressive pseudorheumatoid arthropathy of childhood
  • Spondyloepiphyseal dysplasia tarda with progressive arthropathy

Frequently Asked Questions

PPRD is usually suspected based on a child's symptoms, such as an abnormal walking pattern, joint stiffness, and enlarged joints, typically appearing between ages 3 and 8. Diagnosis is confirmed through genetic testing for mutations in the CCN6 gene. Imaging tests like X-rays can show characteristic skeletal abnormalities, including flattened and abnormally shaped spinal bones and reduced joint space. It's differentiated from juvenile rheumatoid arthritis by the absence of inflammation markers in blood tests and the specific genetic mutation.
Management focuses on symptom relief and maintaining mobility. This often includes physical therapy to improve joint range of motion and muscle strength, occupational therapy for daily activities, and pain management with over-the-counter or prescription medications. Regular, low-impact exercise is encouraged, and assistive devices may be used as needed. Surgical interventions might be considered in some cases to correct severe skeletal deformities or improve joint function.
s PPRD progresses, mobility can become increasingly limited due to cartilage degeneration, pain, and stiffness in all joints, including the spine. Many affected individuals eventually require assistive devices like wheelchairs. For skeletal abnormalities such as kyphoscoliosis, orthopedic specialists can recommend bracing or, in some severe cases, surgical correction to support the spine and improve posture. Regular monitoring by a multidisciplinary team, including orthopedists and physical therapists, is crucial.
Yes, PPRD is caused by mutations in the CCN6 gene, and genetic testing can confirm the diagnosis. It is an autosomal recessive condition, meaning a child must inherit two copies of the mutated gene (one from each parent) to develop the disorder. If you have one child with PPRD, both parents are carriers, and there is a 25% chance of each subsequent child inheriting the condition. Genetic counseling is highly recommended for affected families to understand inheritance patterns and discuss family planning options, including prenatal diagnosis or preimplantation genetic diagnosis.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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