To analyze the molecular etiology of a Chinese child affected with dihydropyrimidinase deficiency.Genomic DNA was extracted from peripheral blood samples of the family members. Pathogenic variant was determined by whole exome sequencing and verified by Sanger sequencing.The child was found to harbor homozygous c.905GA (p.Arg302Gln) variants in exon 5 of the DPYS gene, for which her parents were both heterozygous carriers.The homozygous c.905GA (p.Arg302Gln) variants of the DPYS gene probably underlies the dihydropyrimidinase deficiency in the child. Above result has enabled genetic counseling and prenatal diagnosis for this family.