A novel mutation in FGFR-3 disrupts a putative N-glycosylation site and results in hypochondroplasia.
Fibroblast growth factor receptor 3 (FGFR3) is a glycoprotein that belongs to the family of tyrosine kinase receptors. Specific mutations in the FGFR3 gene are associated with autosomal dominant human skeletal disorders such as hypochondroplasia, achondroplasia, and thanatophoric dysplasia. Hypochondroplasia (HCH), the mildest form of this group of short-limbed dwarfism disorders, results in approximately 60% of cases from a mutation in the intracellular FGFR3-tyrosine kinase domain. The remaining cases may either be caused by defects in other FGFR gene regions or other yet unidentified genes. We describe a novel HCH mutation, the first found outside the common mutation hot spot of this condition. This point mutation, an N328I exchange in the extracellular Ig domain III of the receptor, seems to be unique as it affects a putative N-glycosylation site that is conserved between different FGFRs and species. The amino acid exchange itself most probably has no impact on the three-dimensional structure of the receptor domain, suggesting that the phenotype is the result of altered receptor glycosylation and its pathophysiological consequences.
Winterpacht
A
A
Children's Hospital, University of Mainz, D-55101 Mainz, Germany. winterpacht@uke.uni-hamburg.de
Hilbert
K
K
Stelzer
C
C
Schweikardt
T
T
Decker
H
H
Segerer
H
H
Spranger
J
J
Zabel
B
B
D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004252:DNA Mutational Analysis; D005260:Female; D006031:Glycosylation; D006801:Humans; D007223:Infant; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D010009:Osteochondrodysplasias / Q000235:genetics* / Q000473:pathology; D017354:Point Mutation; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases; D051498:Receptor, Fibroblast Growth Factor, Type 3; D017468:Receptors, Fibroblast Growth Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D017468:Receptors, Fibroblast Growth Factor; D004247:DNA; C496365:FGFR3 protein, human; C496366:Fgfr3 protein, mouse; D011505:Protein-Tyrosine Kinases; D051498:Receptor, Fibroblast Growth Factor, Type 3