Osteopathia striata with cranial sclerosis, associated with juvenile idiopathic arthritis: A case report and review of literature.

Osteopathia striata with cranial stenosis (OSCS) is a rare genetic disorder (Mendelian Inheritance in Man: 300373) inherited in an X-linked dominant pattern. It is classified as a form of skeletal dysplasia and is characterized by linear striations of bone sclerosis, primarily affecting the long bones. OSCS may present as an isolated condition or as part of broader genetic conditions such as Horan-Beighton and Goltz syndromes. Thus far, approximately 100 cases have been reported. Herein, we report the case of an 11-year-old girl with OSCS in association with juvenile idiopathic arthritis (JIA). Osteopathia striata was suspected during the examination in a local healthcare facility due to arthritis. The patient was then transferred to the pediatric rheumatology clinic due to the inefficacy of the first-line systemic immunosuppressive therapy. Genetic analysis revealed a previously unreported AMER1 c.800C>A (p.Ser267*) variant, which was not detected in the healthy mother. Thus, the diagnosis of OSCS was made based on characteristic bone imaging and the presence of likely pathogenic AMER1 variant. This study presents the first detailed description of OSCS occurring in combination with JIA. Diagnosis of OSCS can be challenging due to its rarity and phenotypic heterogeneity. The relationship between JIA and OSCS remains unclear. This case may raise awareness of OSCS.