Prenatal diagnosis of Joubert syndrome

Introduction: Joubert syndrome (JS) is a rare autosomal recessive inherited disease belonging to ciliopathy with the causative mutation of genes. Except for X-linked inheritance, the high recurrence rate of a family is about 25%. After birth, it may cause a series of neurological symptoms, even with retina, kidney, liver, and other organ abnormalities, which is defined as Joubert syndrome and related disorders (JSRD). Molecular genetics research contributes to disease prediction and genetic counseling. Prenatal diagnosis is rare. Magnetic resonance imaging (MRI) is usually the first-choice diagnostic modality with typical brain images characterized by the molar tooth sign. We describe a case of JS prenatally and Dandy-Walker malformation for the differential diagnosis based on ultrasonograms. We also review the etiology, imaging features, clinical symptoms, and diagnosis of JSRD. Casepresentation:A 22-year-old woman was pregnant at 27 1/7 weeks’ gestation with fetal cerebellar vermis hypoplasia. Fetal ultrasonography and MRI confirmed a diagnosis of JS at our center. The couple finally opted to terminate the fetus, which had a normal appearance and growth parameters. The couple also had an AHI1 gene mutation on chromosome 6. Conclusions: Currently, a diagnosis of JS is commonly made after birth. Fewer cases of prenatal diagnosis by ultrasonography have beenmade, and they are more liable to bemisdirected because of some nonspecial features that alsomanifest in Dandy-Walker malformation, cranio-cerebello-cardiac syndrome, and so on. Abbreviations: 4V = fourth ventricle, BS = brain stem, CC = corpus callosum, CH = cerebellar hemisphere, CM = cisterna magna, COACH = cerebellar vermis hypoplasia, oligophrenia of intelligence, ataxia, coloboma of ocular and hepatic fibrosis syndrome, CSP = cavity of septum pellucidum, CV = cerebellar vermis, IF = interpeduncular fossa, JS = Joubert syndrome, JSRD = Joubert syndrome and related disorders, MRI = magnetic resonance imaging, MTS = molar tooth sign, RSCV = remnant of the superior cerebellar vermis, SCP = superior cerebellar peduncle.