Pseudorheumatoid dysplasia. A rare genetic disorder simulating juvenile idiopathic arthritis

Progressive pseudorheumotoid dysplasia: A presentation of four cases with slow and rapid progression and effects of early rehabilitation program

Progressive pseudorheumotoid dysplasia (PPD) is a rare hereditary musculoskeletal disorder which is usually misdiagnosed due to its clinical resemblance to juvenile idiopathic arthritis. It has a high incidence in the Middle East, Gulf States, and countries of Mediterranean basin. Herein, we present four cases of PPD from Turkey (two siblings pair from the same kindred who are far paternal cousins) showing different disease courses. The progression of disease was particularly aggressive in the male sibling who suffered from severe scoliosis with more crippling joint disease. These four cases of PPD support the clinical heterogeneity and variable expressivity of PPD. In this article, we draw attention to the effects of patient education and early rehabilitation which helped to slow progression of range of motion loss.

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.

Mucopolysaccharidosis type IVA (Morquio A): a close differential diagnosis of spondylo-epiphyseal dysplasia

Patients with mucopolysaccharidoses (MPS) have a plethora of multisystemic manifestations depending on the particular type, and atypical presentations are not uncommon. MPS type IVA (Morquio A syndrome) has predominant musculoskeletal system involvement and corneal clouding with normal intelligence and can be misdiagnosed as primary skeletal disorders in clinical practice. The absence of corneal clouding with normal urinary glycosaminoglycans (GAGs) level in a proportion of patients with MPS IVA makes the correct diagnosis even more challenging for physicians. Healthcare providers across specialties should have a high degree of suspicion for MPS IVA in all patients with suspected spondylo-epiphyseal dysplasia as early diagnosis and early treatment significantly improve the clinical outcome and activity of daily living.