Progressive-psuedorheumatoid-arthropathy of childhood (PPAC) is an autosomal recessive single gene skeletal dysplasia involving joints. The gene attributed to its cause is WNT1-inducible-signaling pathway protein3 (WISP3).
To study the clinical and radiographic presentation of PPAC in Indian patients and to compare with described features of PPAC and Juvenile Idiopathic Arthritis (JIA) from published literature.
All cases (n = 14) of PPAC seen in the Rheumatology and Clinical Genetics outpatient clinic between 2008 and 2011 with classical, clinical, and radiological features were studied. The demographic and clinical data were obtained from medical records of the outpatient visits.
Slight female preponderance (57%) and history of consanguinity in parents (43%) was observed in this group. The median age at onset was 4.5 years (range from birth to 9 years of age). Early presentation below the age of 3 years was seen in 3/14 patients (21%) in this group. The growth of all the patients fell below the 3rd percentile for the age. Historically, hip joint involvement was the most common presenting feature; however, elbow, wrist, knees, feet, spine, shoulder joints and small joints, namely proximal interphalangeal (PIP), distal interphalangeal (DIP), metacarpophalangeal (MCP), metatarsophalangeal joints (MTP), and interphalangeal joints (IP) of the feet, were also involved, either clinically or radiologically in varying proportions. Platyspondyly was noted in all. Molecular analysis of the WISP3 gene identified mutations in all the 5 individuals in whom it was done.
This descriptive case series of PPAC from India reports distinctly differentiating clinical, radiological, and molecular markers in contrast with classically described features of JIA, its mimic. Early presentation (age of onset below 3 years) with involvement of interphalangeal joints seen in three patients (21%) was a unique finding, with missense WISP3 gene mutations in all of them. Timely diagnosis of this entity can spare the patient from unnecessary investigations and toxic medications.