[Prenatal diagnosis of Joubert syndrome:one case report and literature review].

A 25-year-old nulliparity underwent prenatal ultrasonography, and the fetal cerebellar abnormality was suspected. The fetal MRI showed 'molar tooth sign' in midbrain and cerebellar vermis hypoplasia. The fetal cerebellar vermis hypoplasia was confirmed by MRI imaging and autopsy after induced abortion. The next-generation sequencing showed that the fetus had a heterozygous mutation of CC2D2A gene (c.2728C > T and c.4598T > C), which might be the cause of the disease.