Aicardi-Goutières syndrome (AGS) is a rare genetic disorder involving the central nervous system and autoimmune abnormalities, leading to severe intellectual and physical disability with poor prognosis. AGS has a phenotype similar to intrauterine viral infection, which often leads to delays in genetic counseling. In this study, a case with a prenatal diagnosis of AGS is reported. The first fetal ultrasound detects bilateral lateral ventricle cystic structures, and fetal MRI is performed to identify other signs. The right parietal lobe signal shows cerebral white matter abnormalities, and fetal brain development level is lower than that of normal fetuses of the same gestational age. Whole-exome sequencing is performed and the final comprehensive diagnosis is AGS1. In this article, also the previous literature for possible phenotypes in the fetus is preformed and the conclusion that microcephaly and intrauterine growth retardation may be the first and most important markers of the intrauterine phenotype of AGS is made. Read the full article here.