Abstract: 　Objectives　To explore the genetic diagnosis of fructose 1,6 diphosphatase deficiency and analysis of mutation sites of its pathogenic genes. Methods　The clinical data and the related results of gene panel screening in one child with fructose 1, 6 diphosphatase (FBPase) deficiency were retrospectively reviewed. Results　The 2-year-old girl suffered repeated infection, nausea, vomiting, mental illness, and drowsiness, accompanied by intermittent convulsions. Blood biochemical tests sμggested hypoglycemia and acidosis. The FBP1 gene had a missense mutation, c.355G>A, p.Asp119Asn (isozygoty). Both her parents carried the locus variation (heterozygous). Conclusions　Fructose 1, 6 diphosphatase deficiency should be considered when child with hypoglycemia after repeated infection, acidosis, and ketosis.