Abstract: 　Objective　To explore the clinical features of KBG syndrome and the characteristics of its gnetic mutation. Method　The clinical data and molecular genetic test results of KBG syndrome in a child were retrospectively analyzed, and the relevant literature was reviewed. Results　A boy aged 1 years and 11 months old visited us for psychomotor retardation, deafness and convulsion. He presented a distinctive appearance such as short stature, ptosis, hypertelorism, epicanthal folds, prominent ears and nasal bridge, bulbous nose, long philtrum, macrodontia of the central incisors, clinodactyly and brachydactyly in the hand. Echocardiography showed patent ductus arteriosus. Video-EEG monitoring showed that the epileptic discharge was localized in bilateral parietal and occipital lobes. Genomic sequencing and bioinformatics analysis showed that there was a novel heterozygous mutation of c.316C>T in exon 6 of ANKRD11 gene, leading to premature termination of protein coding (p.R106X). This mutation was predicted to be pathogenic. So the diagnosis of KBG syndrome was confirmed. A total of 28 articles were retrieved. There are about 200 KBG patients reported in the literature, of whom 71% are with ANKRD11 gene mutations and 29% are with 16q24.3 microdeletions, and the ratio of male to female is 1.5:1. The main clinical manifestations of KBGS patients included craniofacial deformity (99%), giant tooth deformity (84%), mental retardation (90%), behavior problems (60%), bone abnormality (75%), short stature (50%) and hearing abnormality (32%). Conclusions　The mutation spectrum of ANKRD11 gene in KBG syndrome has been expanded, and gene detection is helpful for the early diagnosis of KBG syndrome.

Key words: KBG syndrome;　ANKRD11 gene;　variation