The brittle bone disease .... final cut !

Finally a genetic classification of Osteogenesis Imperfecta has been delineated thanks to efforts of JC Marini and A Forlino. The advances in gene studies and molecular biology led to understanding how a recessive point mutation in a subunits of a tripeptide protein like collagen should have a dominant negative effect. Two kinds of Osteogenesis Imperfecta should be diagnosed: those associated with an autosomal dominant mutation ( AD ) involving the genes coding for procollagen alfa 1 and alfa 2 genes and those involving the genes coding for enzimes involved into procollagen maturation ( AR ).
Now 12 types of Osteogenesis Imperfecta have been described.

References

van Dijk FS, Dalgleish R, Malfait F et al. Clinical utility gene card for: Osteogenesis Imperfecta. Europ J Hum Genet 2013;21:

Forlino A, Cabral WA, Barnes AM et al. New perspective on osteogenesis imperfecta. Nat Rev Endocrinol 2011;7:540-57.

Mannstadt M, Lin AE, Le LP. Case 24-2014 - A 27 year old man with severe osteoporosis and multiple bone fractures. N Engl J Med 2014;371:465-72.