Multicentric Osteolysis Nodulosis Arthropathy Syndrome Simulating Juvenile Idiopathic Arthritis in an Adult Female: A Case Report and a Literature Review.

Multicentric osteolysis, nodulosis, and arthropathy (MONA) syndrome is one of the rare genetic skeletal dysplasias, inherited as an autosomal recessive disorder, which predominantly involves carpal and tarsal bones with characteristic osteolytic lesions and can be misdiagnosed as juvenile idiopathic arthritis or rheumatoid arthritis. MONA syndrome includes diseases involving two genes: the matrix metalloproteinase 2 (MMP2) gene and matrix metalloproteinase 14 (MMP14). Both genes are assumed to cause phenotype variants of the same disease. Older patients may manifest some arthritic features, especially in the wrist, and minute pathological fractures can occur as well. These patients may be misdiagnosed as inflammatory arthritis and physicians might prescribe corticosteroid and disease-modifying immunosuppressive agents. Therefore, physicians should carefully evaluate genetic skeletal dysplasia to make a correct diagnosis and avoid unnecessary pharmacological intervention. We report a case of MONA syndrome in an adult female who came to our facility for an intensive rehabilitation program.

Differential requirements for the EF-hand domains of human centrin 2 in primary ciliogenesis and nucleotide excision repair.

Centrin 2 is a small conserved calcium-binding protein that localizes to the centriolar distal lumen in human cells. It is required for efficient primary ciliogenesis and nucleotide excision repair (NER). Centrin 2 forms part of the xeroderma pigmentosum group C protein complex. To explore how centrin 2 contributes to these distinct processes, we mutated the four calcium-binding EF-hand domains of human centrin 2. Centrin 2 in which all four EF-hands had been mutated to ablate calcium binding (4DA mutant) was capable of supporting in vitro NER and was as effective as the wild-type protein in rescuing the UV sensitivity of centrin 2-null cells. However, we found that mutation of any of the EF-hand domains impaired primary ciliogenesis in human TERT-RPE1 cells to the same extent as deletion of centrin 2. Phenotypic analysis of the 4DA mutant revealed defects in centrosome localization, centriole satellite assembly, ciliary assembly and function and in interactions with POC5 and SFI1. These observations indicate that centrin 2 requires calcium-binding capacity for its primary ciliogenesis functions, but not for NER, and suggest that these functions require centrin 2 to be capable of forming complexes with partner proteins.This article has an associated First Person interview with the first author of the paper.