Prenatal diagnosis of Joubert syndrome: A case report.

Joubert syndrome (JS) is a rare autosomal recessive disorder with brain stem and cerebellar malformations. Early diagnosis through Magnetic Resonance Imaging (MRI) and ultrasonography (US) is crucial for managing this condition. This report presents a JS case diagnosed at 24 weeks of pregnancy. A 25-year-old gravida 2, para 1 woman was referred at 24 weeks' gestation for suspected posterior fossa abnormalities. Ultrasound revealed normal cerebellar hemispheres but significant abnormalities in the cerebellar vermis, including the molar tooth sign and polydactyly, suggesting JS. The fetal MRI confirmed these findings. Following specialist consultations, the patient opted to terminate the pregnancy. A stillborn female infant was delivered, and genomic DNA sequencing identified a frameshift deletion in the AHI1 gene. Early prenatal diagnosis of JS is crucial for informed pregnancy management. The combination of ultrasonography, MRI, and genomic DNA sequencing proved effective for diagnosis.