For instance, three different mutations in FGFR3, G346E, G375C, and G380R have been linked to achondroplasia (ACH), the most common form of human dwarfism, while several other mutations in the same receptor (R240C, R248C, S249C, 370C, S371C, Y373C, and K650E) cause the much more severe and lethal thanatophoric dysplasia type 1 (TD1) [10], [11], [22]. The gene discussed is FGFR3; the disease is thanatophoric dysplasia type 1.