Australian Rotary Health

Craniosynostosis, a condition that affects 1 in 2500 live births, is a condition wherein sutures, the fibrous joins between skull bones, turn to bone. This prevents further growth of the skull and consequently restricts the rapid expansion of the head during infancy, which is required to allow for brain growth. 

This can result in raised pressure inside the skull, mental retardation, misshapen eye sockets and difficulties with breathing and hearing.

 

Recent studies have found RBP4 was found in significantly less quantities in the sutures of patients with craniosynostosis, compared to those without. This became the focus of this study as it is known that changes in the vitamin A signalling pathways can promote bone growth. 

 

Vitamin A and its metabolite retinoic acid had previously been implicated as a possible cause of craniosynostosis, as abnormal growth could result should a child be exposed to higher than normal doses of vitamin A during pregnancy.

 

The present study has identified expression of RBP4, and its cell surface receptor STRA6 in cells from the suture. Additionally, as RBP4 levels decreased, STRA6 levels increased. This inverse relationship between RBP4 and STRA6, may be linked to the suture fusion occurring.

 

Finally, RBP4 was found to stay in a particular location inside the cells of the suture, which may indicate a role in these cells for vitamin A storage.

 

Within 10 years, we would hope to see this information allowing for treatments to prevent the re-growth of this abnormal bone. This would eliminate the need for repeated surgeries in these children.

 

This study was the first to look at the potential roles of RBP4 during abnormal bone growth. 

 

The findings from this study, in particular the relationship between RBP4 and STRA6 levels, and the location of RBP4 in the suture cells are the first to show that RBP4 may be playing a role in these cells.