Background:TBL1XR1, also known asIRA1orTBLR1, encodes a protein that is localized in the nucleus and is expressed in most tissues. TBL1XR1 binds to histones H2B and H4in vitro and functions in nuclear receptor-mediated transcription. TBL1XR1 is also involved in the regulation of the Wnt–β-catenin signaling pathway. Mutations in theTBL1XR1gene impair the Wnt–β-catenin signaling pathway’s ability to recruit Wnt-responsive element chromatin, affecting brain development. Mutations in this gene cause various clinical phenotypes, including Pierpont syndrome, autism spectrum disorder, speech and motor delays, mental retardation, facial dysmorphism, hypotonia, microcephaly, and hearing impairment.Case Summary:A 5-month-old female child was admitted with “episodic limb tremors for more than 1 month.” At the time of admission, the child had recurrent episodes of limb tremors with motor retardation and a partially atypical and hypsarrhythmic video electroencephalogram. It was determined that a heterozygous mutation in theTBL1XR1gene caused West syndrome and global developmental delay. Recurrent episodes persisted for 6 months following oral treatment with topiramate; the addition of oral treatment with vigabatrin did not show any significant improvement, and the disease continued to recur. The child continued to have recurrent episodes of limb tremors at follow-up until 1 year and 3 months of age. Additionally, she developed poor eye contact and a poor response to name-calling.Conclusion:We report the case of a child with West syndrome and a global developmental delay caused by a heterozygous mutation in theTBL1XR1gene. This study adds to our understanding of the clinical phenotype ofTBL1XR1mutations and provides a realistic and reliable basis for clinicians.