Osteoglophonic dysplasia (OGD)

(OMIM phenotype number #166250)


Osteoglophonic dysplasia (OGD) is a very rare skeletal disease caused by activating mutations in a highly conserved domain in the gene encoding fibroblast growth factor receptor-1 (FGFR1). The name “osteoglophonic” was derived from the Greek word meaning a “hollowed-out” appearance of bone. Beighton called this disorder OGD in his review published in 1989. It is transmitted in an autosomal dominant manner. The FGFRs are part of a tyrosine kinase receptor family. They comprise an extracellular ligand-binding domain, a single transmembrane domain, and an intracellular tyrosine kinase region. FGFR1 and FGFR2 mutations cause syndromes involving craniosynostosis whereas FGFR3 mutations are associated with dwarfing syndromes such as achondroplasia and hypochondroplastic dwarfism. OGD shares characteristics with both the craniosynostosis and dwarfing syndromes. The main radiographic features include: craniostenosis, fibrous dysplasia, metaphyseal lucencies and platyspondyly.

Gene

FGFR1 gene, 9p11.23-p11.22 (OMIM gene/locus number #136350).

Phenotype

Craniofacial abnormalities, macroglossia,  hypertrophy of the gums, severe dwarfism, mandibular prognathism, frontal bossing, and proptosis; gross stunting of stature, rickets/osteomalacia, severe craniofacial abnormalities, and bone dysplasia.

Main biochemical alterations

High Ur P, low Pi, low renal TmP/GFR, normal Ca, low-normal Ur Ca, normal 25 OH D; low-normal 1,25(OH)2D, and high bone ALP, high/normal intact FGF23, normal PTH.

References

  1. White KE, Cabral JM, Davis SI, et al. Mutations that cause osteoglophonic dysplasia define novel roles for FGFR1 in bone elongation. Am J Hum Genet. 2005 Feb;76(2):361-7.
  2. Shankar VN, Ajila V, Kumar G. Osteoglophonic dysplasia: a case report. J Oral Sci. 2010 Mar;52(1):167-71.
  3. Sow AJ, Ramli R, Latiff ZA, et al. Osteoglophonic dysplasia: A 'common' mutation in a rare disease. Clin Genet. 2010 Aug;78(2):197-8.
  4. Masi L, Agnusdei D, Bilezikian J et al. Taxonomy of rare genetic metabolic bone disorders. Osteoporos Int. 2015 Jun 13.
  5. http://www.omim.org