Thanatophoric dysplasia

Achondroplasia (MIM 100800) and thanatophoric dysplasia (MIM 187600) Mutations In the gene encoding FGFR3. 

The primary mutation in achondroplasia results in a defect in internalization and degradation of the mutant receptor. Thus it is retained on the ceE surface and has uncontrolled and prolonged activation in chondrocytes. Hence, chondrocyte maturation and terminal differentiation are inhibited. Following the discovery of the association between achondroplasia and FGFR3 mutations, other similar gain-of-function mutations at other sites within this gene have been identified as the cause of less common forms of dwarfism, including thanatophoric dysplasia types I and n and hypochondroplasia. ... 

Tavormina P, Shiang R, Thompson L, Zhu Y, Wilkin D, Lachman R, et al. Thanatophoric dysplasia (types I and II) caused by distinct mutations in fibroblast growth factor receptor 3. Nat Genet 1995 9 321-8. 

Thanatophoric (Gk thanatos "death" + pharos "bearing") dysplasia is the most common neonatal lethal skeletal dysplasia, displaying features similar to those of homozygous achondroplasia. 

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