Biomechanics of walking in adolescents with progressive pseudorheumatoid arthropathy of childhood leads to physical activity recommendations as therapeutic focus

Gait Alterations in Two Young Siblings with Progressive Pseudorheumatoid Dysplasia

Progressive pseudorheumatoid dysplasia (PPRD) is an autosomal recessive inherited skeletal dysplasia characterized by progressive non-inflammatory arthropathy affecting primarily the articular cartilage. Currently, little is known about the functional musculoskeletal aspects of these patients. In particular, an abnormal gait pattern has been described, without a clear hypothesis of the underlying causes in terms of muscular activity. This study presents the case of two siblings, 4 and 9 years old, a boy and a girl, respectively, suffering from PPRD at different stages of the disease. In addition to the clinical assessment, an instrumental gait analysis was performed. Swelling of the interphalangeal finger joints and fatigue were present in both cases. Gait abnormalities consisted of a relevant reduction in the ankle plantarflexion in the terminal phase of the gait cycle, associated with reduced gastrocnemius EMG activity and increased activity of the tibialis anterior, resulting in overloading at the initial peak of ground reaction forces. Gait anomalies observed were similar in both siblings with PPRD, although at different ages, and confirm walking patterns previously described in the literature. The calf muscle strength deficit and reduced activity during the stance phase of gait present in these two siblings indicate the typical absence of the propulsive phase. A stomping gait pattern, with the foot striking the ground hard on each step, was originally described. Further neurophysiological investigations are required to determine the origin of muscle weakness.

Specific early signs and long-term follow-up findings of Progressive Pseudorheumatoid Dysplasia (PPRD) in the Turkish cohort

OBJECTIVES

Progressive pseudorheumatoid dysplasia (PPRD) is a spondyloepiphyseal dysplasia caused by biallelic variants in CCN6. This study aimed to describe the early signs and follow-up findings in forty-four Turkish PPRD patients.

METHODS

The patients with progressive stiffness of multiple joints, characteristic wide metaphysis of interphalangeal (IP) joints, and platyspondyly were clinically diagnosed with PPRD. Fifteen patients who had first symptoms under 3 years of age were grouped as early-onset, while others were grouped as classical. CCN6 sequencing was performed in 43 patients.

RESULTS

Thirteen pathogenic/likely pathogenic variants were identified, five were novel. c.156C>A(p.Cys52*) variant was found in 53.3% of the families. The initial symptom in the early-onset group was genu varum deformity, while it was widening of IP joints in the classical group. The median age of onset of symptoms and of diagnosis was 4 and 9.7 years, respectively. The mean follow-up duration was 5.6 years. The median age of onset of IP, elbow, knee, and hip stiffness, which became progressive with growth was 5, 9, 9, and 12.2 years, respectively. Waddling gait occurred in 97.7% of the patients. 47.7% lost independent walking ability at the median age of 12 years. In the early-onset group, waddling gait occurred earlier than in classical group (p< 0.001). Two patients had atypical presentation with late-onset and mild or lack of IP involvement.

CONCLUSION

We observed that genu varum deformity before the age of 3 years was an early sign for PPRD and almost half of the patients lost walking ability at the median age of 12 years.

Progressive pseudorheumatoid dysplasia: a rare childhood disease

Progressive pseudorheumatoid dysplasia (PPRD) is a genetic bone disorder characterised by the progressive degeneration of articular cartilage that leads to pain, stiffness and joint enlargement. As PPRD is a rare disease, available literature is mainly represented by single case reports and only a few larger case series. Our aim is to review the literature concerning clinical, laboratory and radiological features of PPRD. PPRD is due to a mutation in Wnt1-inducible signalling protein 3 (WISP3) gene, which encodes a signalling factor involved in cartilage homeostasis. The disease onset in childhood and skeletal changes progresses over time leading to significant disability. PPRD is a rare condition that should be suspected if a child develops symmetrical polyarticular involvement without systemic inflammation, knobbly interphalangeal joints of the hands, and gait abnormalities. A full skeletal survey, or at least a lateral radiograph of the spine, can direct towards a correct diagnosis that can be confirmed molecularly. More than 70 WISP3 mutations have so far been reported. Genetic testing should start with the study of genomic DNA extracted from blood leucocytes, but intronic mutations in WISP3 causing splicing aberrations can only be detected by analysing WISP3 mRNA, which can be extracted from cultured skin fibroblasts. A skin biopsy is, therefore, indicated in patients with typical PPRD findings and negative mutation screening of genomic DNA.

Progressive pseudorheumatoid dysplasia with new-found gene mutation of Wntl inducible signaling pathway protein 3

BACKGROUND

As one kind of osteochondrodysplasia, progressive pseudorheumatoid dysplasia (PPD) is also known as spondyloepiphyseal dysplasia tarda with progressive arthropathy or arthropathy progressive pseudorheumatoid of childhood. PPD is a very rare disease, especially in China, and has an estimated prevalence of 1/1000000 due to lacking definite prevalence survey. It is an autosomal recessive disorder caused by gene mutation of Wntl inducible signaling pathway protein 3 (WISP3). Its basic pathological change is persistent degeneration and loss of articular cartilage in multiple joints. Its clinical appearances include bone enlargement, platyspondyly, irregular endplate, secondary osteoarthritis, extensive osteoporosis, joint rigidity and function loss. Clinical diagnosis of PPD is made based on clinical appearance and imaging examinations, whereas its definite diagnosis depends on gene sequencing. PPD has no severe effect on life span, but causes high disability rate and very poor prognosis. There are only case reports with limited information in China.

CASE PRESENTATION

One female patient was diagnosed as PPD and secondary osteoarthritis. She had typical clinical appearance and imaging examinations, and received individualized therapeutic regimens. She had a gene mutation (c.72delT, p.T24TfsX4) of WISP3. This gene mutation has not been reported by previous literatures and included in Single Nucleotide Polymorphism Database.

CONCLUSIONS

As the first time, this paper reported a patient with PPD caused by new-found gene mutation (c.72delT, p.T24TfsX4) of WISP3.