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Introduction: Cranio-cervical anomalies are significant complications of osteogenesis imperfecta (OI), a rare bone fragility disorder that is usually caused by mutations in collagen type I encoding genes., Objective: To assess cranio-cervical anomalies and associated clinical findings in patients with moderate-to-severe OI using 3D cone beam computed tomography (CBCT) scans., Methods: Cross-sectional analysis of CBCT scans in 52 individuals with OI (age 10-37 years; 32 females) and 40 healthy controls (age 10-32 years; 26 females). Individuals with a diagnosis of OI type III (severe, n = 11), type IV (moderate, n = 33) and non-collagen OI (n = 8) were recruited through the Brittle Bone Disorders Consortium. Controls were recruited through the orthodontic clinic of the University of Missouri-Kansas City (UMKC)., Results: OI and control groups were similar in mean age (OI: 18.4 [SD: 7.2] years, controls: 18.1 [SD: 6.3] years). The cranial base angle was increased in the OI group (OI: mean 148.6° [SD: 19.3], controls: mean 130.4° [SD: 5.7], P = .001), indicating a flatter cranial base. Protrusion of the odontoid process into the foramen magnum (n = 7, 14%) and abnormally located odontoid process (n = 19, 37%) were observed in the OI group but not in controls. Low stature, expressed as height z-score (P = .01), presence of DI (P = .04) and being male (P = .04) were strong predictors of platybasia, whereas height z-score (P = .049) alone was found as positive predictor for basilar impression as per the Chamberlain measurement., Conclusion: The severity of the phenotype in OI, as expressed by the height z-score, correlates with the severity of cranial base anomalies such as platybasia and basilar impression in moderate-to-severe OI. Screening for cranial base anomalies is advisable in individuals with moderate-to-severe OI, with special regards to the individuals with a shorter stature and DI., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Osteogenesis imperfecta (OI) is a rare bone disease that is associated with fractures and low bone mass. Sclerostin inhibition is being evaluated as a potential approach to increase bone mass in OI. We had previously found that in Col1a1 Jrt/+ mice, a model of severe OI, treatment with an anti-sclerostin antibody had a minor effect on the skeletal phenotype. In the present study, we assessed the effect of genetic sclerostin inactivation in the Col1a1 Jrt/+ mouse. We crossed Col1a1 Jrt/+ mice with Sost knockout mice to generate Sost-deficient Col1a1 Jrt/+ mice and assessed differences between Col1a1 Jrt/+ mice with homozygous Sost deficiency and Col1a1 Jrt/+ mice with heterozygous Sost deficiency. We found that Col1a1 Jrt/+ mice with homozygous Sost deficiency had higher body mass, femur length, trabecular bone volume, cortical thickness and periosteal diameter as well as increased biomechanical parameters of bone strength. Differences between genotypes were larger at the age of 14 weeks than at 8 weeks of age. Transcriptome analysis of RNA extracted from the tibial diaphysis revealed only 5 differentially regulated genes. Thus, genetic inactivation of Sost increased bone mass and strength in the Col1a1 Jrt/+ mouse. It appears from these observations that the degree of Sost suppression that is required for eliciting a beneficial response can vary with the genetic cause of OI., (© 2023. The Author(s).)

Osteogenesis imperfecta (OI) is a bone fragility disorder that is usually caused by mutations affecting collagen type I. We compared the calvaria bone tissue transcriptome of male 10-week-old heterozygous Jrt ( Col1a1 mutation) and homozygous oim mice ( Col1a2 mutation) to their respective littermate results. We found that Jrt and oim mice shared 185 differentially expressed genes (upregulated: 106 genes; downregulated: 79 genes). A total of seven genes were upregulated by a factor of two or more in both mouse models ( Cyp2e1 , Slc13a5 , Cgref1 , Smpd3 , Ifitm5 , Cthrc1 and Rerg ). One gene ( Gypa , coding for a blood group antigen) was downregulated by a factor of two or more in both OI mouse models. Overrepresentation analyses revealed that genes involved in 'ossification' were significantly overrepresented among upregulated genes in both Jrt and oim mice, whereas hematopoietic genes were downregulated. Several genes involved in Wnt signaling and transforming growth factor beta signaling were upregulated in oim mice, but less so in Jrt mice. Thus, this study identified a set of genes that are dysregulated across various OI mouse models and are likely to play an important role in the pathophysiology of this disorder.

Sphingomyelin phosphodiesterase 3 (SMPD3) is a pleiotropic lipid metabolizing enzyme involved in multiple physiological processes. A deletion mutation in the murine Smpd3 gene called fragilitas ossium (fro) leads to severe skeletal abnormalities in the developing fro/fro embryos. Although fro/fro mice can be useful to study many different aspects of SMPD3 functions, their perinatal lethality makes it difficult to generate a sufficient number of mice for controlled studies. In fact, on the C57BL/6 genetic background, none of the fro/fro mice survive beyond the perinatal stage. In this study, we used the "Tet-On" inducible gene expression system to express Smpd3 transiently in fro/fro;ROSA-rtTA;TRE-Smpd3 embryos on the C57BL/6 background. This induced Smpd3 expression corrected all the skeletal abnormalities in these embryos and prevented their early death. However, induction of Smpd3 expression in the adolescent fro/fro;ROSA-rtTA;TRE-Smpd3 mice was not sufficient to correct the defects in trabecular bone mineralization and the impaired growth of the long bones. This novel mouse model will be a useful tool to study SMPD3 biology in vivo., (© 2014 Wiley Periodicals, Inc.)

Objective: Osteogenesis imperfecta (OI) is an autosomal dominant genetic disease that mainly affects the COL1A1/A2 genes. Individuals affected by OI types I, III, and IV have been reported to demonstrate characteristic facial manifestations of the disease. This study aimed to quantitatively assess OI patients' morphological characteristics. Materials and Methods: This retrospective case‐control study involved 306 individuals (145 male and 161 female). It used automatic facial annotation and statistical shape analysis to compare facial photographs of individuals affected by OI types I, III, and IV with a normocephalic control group. Four facial ratios were used to compare facial proportions. Additionally, we proposed a novel approach to facial analysis using 68 landmarks and statistical shape analysis to compare morphological features. A predictive model (PCALog) was trained to detect whether a subject was affected by OI, based on facial landmarks. Results: Our findings correlate with previous reports of OI type III patients' facial characteristics being the most severely affected among the three types studied. Our novel approach facilitated an interpretation and comparison of morphological changes. Moreover, we successfully trained our PCALog model to automatically detect OI based on landmark features. Conclusion: We found patients' facial manifestations of OI to be more pronounced at the level of the eyes and temples. Our morphological approach facilitates the comparison of various groups and should be considered for future craniofacial analysis studies. Machine learning models can be trained using facial landmarks to detect the presence of conditions that affect facial morphology. [ABSTRACT FROM AUTHOR]