The FGFR3 gene encodes Fibroblast Growth Factor Receptor 3, a transmembrane receptor tyrosine kinase that plays a crucial role in regulating cell growth, differentiation, and apoptosis. It is widely expressed in various tissues, including the brain, kidney, testis, lung, small intestine, and liver, but is particularly important in cells forming bones, especially within the growth plate of cartilage ^[1]. The Fdfr3*Y367C mutation, which corresponds to the human Y373C mutation (a gain-of-function mutation), leads to constitutive activation of the FGFR3 protein. This overactivity disrupts normal chondrocyte proliferation and differentiation, impairing endochondral ossification and linear bone growth ^[2]. As a result, this mutation is significantly associated with severe skeletal dysplasias, including Thanatophoric Dysplasia type I (TDI) and Achondroplasia (ACH), the most common form of short-limbed dwarfism, characterized by disproportionate short stature, macrocephaly, and other skeletal deformities ^[3]. Y373C is one of the common activating mutations of FGFR3, accounting for approximately 50% of patients with thanatophoric dysplasia (TD-type I), but a lower proportion in the more prevalent achondroplasia (ACH) (ACH is primarily dominated by the G380R mutation). In reported literature, the Fgfr3*Y367C mutation is typically used to construct mouse models in a heterozygous form, which corresponds to the heterozygous nature of this mutation in human clinical patients. Its dominant-negative effect is sufficient to cause the disease ^[4].

Fgfr3-Y367C(neo del) mice are a neo‑free disease model generated by crossing Fgfr3‑neoY367C mice (catalog No.: C001745) with Flpo mice. Internal data indicate that double heterozygous offspring die around postnatal day 22 (P22). This model can be used to study disease mechanisms and therapeutic approaches for achondroplasia (ACH), thanatophoric dysplasia (TD), and related conditions.