Abstract: 　Objective　To investigate the clinical features and gene mutation of Temple-Baraitser syndrome (TMBTS). Methods　The clinical data of a male infant with TMBTS were retrospectively analyzed. The clinical manifestations and genetic mutations of children with TMBTS were summarized. Results　The 7-month-old male proband visited our clinic because of motor developmental delay for half a year. The infant presented with marked hypotonia and poor visual contact during the neonatal period. His face was myopathic and he had a flat forehead, hypertelorism, broad depressed nasal bridge, thick alae nasi, full cheeks, long shallow philtrum, and a broad mouth with downturned corners. Nails were hypoplastic on both thumbs and great toes. Halluces were unusually long and tubular. The other fingernails were slightly hypoplastic. He was unable to hold his head up, grip toy, turn over, sit, and creep. His muscle strengths of limbs were of grade IV. The knee jerk reflex was normal. Pathological signs were negative. Whole exome sequencing of the proband and his parents revealed a de novo missense mutation in the TMBTS infant: c.1136T>C, p.Leu379Pro in KCNH1. This mutation in KCNH1 was predicted to be damaging. In addition, literatures review showed clinical features of TMBTS is resemble to that of ZimmermannLaband syndrome. More information of KCNH1 mutations and detailed clinical features are needed to distinguish these two syndromes. Conclusions　Our findings expand the mutational spectrum of KCNH1 in TMBTS, which provides a basis for the diagnosis, treatment and genetic counseling of TMBTS.

Key words: Temple-Baraitser syndrome;　developmental disorder;　KCNH1 gene;　missense mutation;　infant