TAPT1 (transmembrane anterior posterior transformation 1) is a transmembrane protein that functions as a critical regulator of multiple developmental processes, particularly skeletal and neural development. The protein localizes to centrosomes and ciliary basal bodies, where it plays an essential role in ciliogenesis and primary cilium formation 1. TAPT1 acts as a negative regulator of BMP signaling by facilitating SMAD1/5 protein degradation through interaction with SMURF1 E3 ubiquitin ligase, thereby controlling osteogenic differentiation 2. Additionally, TAPT1 interacts with SUCO in the endoplasmic reticulum to maintain homeostasis of newly synthesized proteins crucial for brain development 3. Bi-allelic mutations in TAPT1 cause complex lethal osteochondrodysplasia (Symoens-Barnes-Gistelinck type), characterized by severe skeletal hypomineralization, intra-uterine fractures, and multi-organ developmental anomalies affecting brain, lungs, and kidneys 1. The phenotypic spectrum ranges from isolated early-onset cataract to severe syndromic disease 4. TAPT1 deficiency disrupts Golgi morphology, impairs ER-to-Golgi trafficking, and causes defective neural progenitor cell proliferation and differentiation, leading to microcephaly and motor dysfunction 3. The protein's role in maintaining cellular homeostasis makes it essential for proper embryonic development and adult tissue maintenance.