Vitamin K status in Children with Osteogenesis Imperfecta

Children with the rare genetic disease Osteogenesis Imperfecta (O.I.) are prone
to fracture bones. This latter is caused by a defect or decreased production of
the protein in the bone that accounts for their strength, collagen-1. Because
of this defective collagen, bones are degraded and build again faster compared
to children without O.I. Optimal vitamin K levels are vital for bone quality
and growth, however, the vitamin K status in children with O.I. it is currently
unknown. Therefore, to investigate whether blood levels of vitamin K are lower
in children with O.I. compared to children without O.I can provide new
insights of bone quality and growth in this population. If levels are indeed
lower compared to children with O.I. this could provide a relative simple
window of opportunity to improve quality and growth of bone in these children
as well as lowering the amount of fractures. Vitamin K can easily and safely be
suppleted, but however has never been investigated in children with O.I.
Therefore, the primary aim of the current study is to determine the vitamin K
levels in children with O.I. and compare these compared to children without
O.I.. If the vitamin K levels are decreased, we have sound scientific grounds
to start a new study on the effects of vitamin K suppletion on bone strength
and growth in children with O.I., which might result in fewer bone fractures,
better growth, and quality of life.

We want to investigate whether blood levels of vitamin K are lower in children
with O.I. compared to children without O.I.

During 1 year children (0-18 y) with O.I. who regularly get bisphosphonate
infusions at UMCU will be included in our study. We will use informed consent
to ask for permission to take 1x a blood sample via the intravenous line.
Parallel children who need to undergo surgery within the UMC Utrecht will be
included in our study. The blood samples will be analyzed for Vitamin K and
bone markers (by means of ELISA-like tests). Each blood sample that is
collected, will be used to measure the named markers and results will be
analyzed. At the end of project all data will be put together and a final
analysis will be done Then, these results will be published in an international
scientific journal and communicated to the OI patients via the patient support
group ( VOI)

We are interested in the vitamin K status of children with O.I., since they
still grow and this is the period in life fractures are most common and the
effect of possible vitamin K suppletion will be highest, when we find a vitamin
K deficiency.
Blood (9 ml) is drawn once from the infuse line that is necessary for planned
treatment during a regular visit to the center. This will therefore not induce
extra pain or stress to the child. We expect that possible negative effects of
blood withdrawal will be negligible: the child in every case will be lying down
for some time after withdrawal because of the regular treatment that is started
after our sampling.
The results will give direct indications about the possible deficiency of
vitamin K in participating children. When a vitamin K deficiency is found in
children with O.I., we will be able to start an intervention study with vitamin
K shortly, since this supplement has been found already to be safe in adults as
well as in children. When eventually would be proven that vitamin K has a
positive effect on growth and amount of fractures in O.I., it will improve
quality of life of children with O.I., possibly already the children that take
part in our study.