An in vivo reporter of BMP signaling in organogenesis reveals targets in the developing kidney.

Background: Bone morphogenetic proteins (BMPs) regulate essential processes during organogenesis, and a functional understanding of these secreted proteins depends on identification of their target cells. In this study, we generate a transgenic reporter for organogenesis studies that we use to define BMP pathway activation in the developing kidney.

Results: Mouse strains reporting on BMP pathway activation were generated by transgenically expressing beta-galactosidase under the control of BMP responsive elements from Id1.

Syndromic craniosynostosis: from history to hydrogen bonds.

The syndromic craniosynostoses, usually involving multiple sutures, are hereditary forms of craniosynostosis associated with extracranial phenotypes such as limb, cardiac, CNS and tracheal malformations. The genetic etiology of syndromic craniosynostosis in humans is only partially understood. Syndromic synostosis has been found to be associated with mutations of the fibroblast growth factor receptor family (FGFR1, -R2, -R3), TWIST1, MSX2, and EFNB1.

Isolated sagittal and coronal craniosynostosis associated with TWIST box mutations.

Craniosynostosis, the premature fusion of one or more cranial sutures, affects 1 in 2,500 live births. Isolated single-suture fusion is most prevalent, with sagittal synostosis occurring in 1/5,000 live births. The etiology of isolated (nonsyndromic) single-suture craniosynostosis is largely unknown.

Intracellular retention, degradation, and signaling of glycosylation-deficient FGFR2 and craniosynostosis syndrome-associated FGFR2C278F.

Fibroblast growth factors (FGFs) and their receptors (FGFRs) are known to play a critical role in a variety of fundamental processes, including wound healing, angiogenesis, and development of multiple organ systems. Mutations in the FGFR gene family have been linked to a series of syndromes (the craniosynostosis syndromes) whose primary phenotype involves aberrant development of the craniofacial skeleton. Craniosynostosis syndrome-linked FGFR mutations have been shown to be gain of function in terms of receptor activation and have been presumed to result in increased levels of FGF/FGFR signaling.

Cleidocranial dysplasia with severe parietal bone dysplasia: C-terminal RUNX2 mutations.

Background: Cleidocranial dysplasia (CCD) is an autosomal-dominant skeletal dysplasia syndrome that is characterized by widely patent calvarial sutures, clavicular hypoplasia, supernumerary teeth, and short stature. CCD is caused by mutations in the transcription factor RUNX2, which is known to function as a major regulator of bone differentiation. Despite the characterization of 67 unique mutations in 97 individual cases, and the availability of animal models, no obvious genotype-phenotype correlation has emerged.

In vitro differentiation profile of osteoblasts derived from patients with Saethre-Chotzen syndrome.

Seathre-Chotzen syndrome (SCS) is an autosomal dominant craniosynostosis syndrome, associated with loss-of-function mutations in the basic helix-loop-helix transcription factor, TWIST1. The biologic activity of TWIST1 has been implicated in the inhibition of differentiation of multiple cell lineages. Therefore, premature fusion of cranial sutures (craniosynostosis) in SCS may be mediated by altered differentiation of calvarial osteoblasts.

Progressive postnatal craniosynostosis and increased intracranial pressure.

Since its first description by Virchow in 1851, craniosynostosis has been known as a potentially serious condition resulting in premature fusion of skull sutures. Traditionally, craniosynostosis has been regarded as an event that occurs early in fetal development, resulting in a skull shape at birth that is determined by the suture or sutures involved. In recent years, a different form of craniosynostosis has been observed.