The inherited osteolyses or 'vanishing bone' syndromes are a group of rare disorders of unknown etiology characterized by destruction and resorption of affected bones. The multicentric osteolyses are notable for interphalangeal joint erosions that mimic severe juvenile rheumatoid arthritis (OMIMs 166300, 259600, 259610 and 277950). We recently described an autosomal recessive form of multicentric osteolysis with carpal and tarsal resorption, crippling arthritic changes, marked osteoporosis, palmar and plantar subcutaneous nodules and distinctive facies in a number of consanguineous Saudi Arabian families. We localized the disease gene to 16q12-21 by using members of these families for a genome-wide search for homozygous-by-descent microsatellite markers. Haplotype analysis narrowed the critical region to a 1.2-cM region that spans the gene encoding MMP-2 (gelatinase A, collagenase type IV; (ref. 3). We detected no MMP2 enzymatic activity in the serum or fibroblasts of affected family members. We identified two family-specific homoallelic MMP2 mutations: R101H and Y244X. The nonsense mutation effects a deletion of the substrate-binding and catalytic sites and the fibronectin type II-like and hemopexin/TIMP2 binding domains. Based on molecular modeling, the missense mutation disrupts hydrogen bond formation within the highly conserved prodomain adjacent to the catalytic zinc ion.

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Objective The Arab League of Associations for Rheumatology (ArLAR) Research Group (ARCH) conducted this study to investigate the number of current practicing rheumatologists in the Arab countries, to estimate the number of rheumatologists in 10 years, and to evaluate the current workload, practice profile, consultation waiting time and geographical mobilities of these rheumatologists. Methods This cross-sectional survey study was conducted in 16 Arab countries in two parts. The first survey was addressed to national societies to estimate the current and projected workforce. The second was an anonymous e-survey elaborated by the study steering committee on the Google Forms platform and distributed to Arab rheumatologists using social media, WhatsApp, and mass e-mails to evaluate their practice. Results The mean number of rheumatologists in Arab countries was 0.84 per 100,000 inhabitants (mean age 47.5 years, 55% females), ranging from 0.06 in Sudan to 1.86 in Tunisia. The number of rheumatologists is expected to increase by 50% in 2032. Nevertheless, a 20% increase in population associated with an increase in demand is also expected. Data from 446 rheumatologists (mean age 43.9 years, 60.5% females) revealed that 72% worked full-time, and 53% were employed in the public sector only. The average waiting time for a rheumatology consultation was 19.9 days. Of 394 rheumatologists, 19% obtained their rheumatology diplomas from non-Arab countries, and 47% of Gulf rheumatologists were non-citizen physicians. Conclusion Considering local demographic disparities, healthcare system differences, and geographical mobilities, national authorities are advised to implement effective intervention plans to optimize the rheumatology workforce.