Thanatophoric Dysplasia Type I Confirmed by Fibroblast Growth Factor Receptor 3 (FGFR3) Mutation: Clinical Course and Ethical Considerations.

Thanatophoric dysplasia (TD) is the most common lethal skeletal dysplasia, caused by de novo fibroblast growth factor receptor 3 (FGFR3) mutations. Prenatal ultrasound may detect key features such as severe micromelia, narrow thorax, macrocephaly, and temporal lobe dysplasia, although molecular confirmation is essential. Type I TD (TD1), the most frequent subtype, shows "telephone-receiver" femur bowing, frontal bossing, and midface hypoplasia. Type II TD presents with a cloverleaf skull and straight femurs. TD is generally fatal due to pulmonary hypoplasia, narrow thorax, and brainstem compression, with survival beyond the early neonatal period being uncommon. We report a newborn with prenatal suspicion of skeletal dysplasia, confirmed postnatally as TD1 via FGFR3 p.Ter807Trp mutation, highlighting the importance of prenatal counseling, early genetic confirmation, and palliative care involvement.