Enlarged Intracranial Translucency, as a Potential Marker for Diagnosis of Joubert Syndrome during First-Trimester Screening: A Case Report

Abstract Joubert syndrome (JS) is a rare autosomal recessive neurodevelopmental disorder that is usually diagnosed late in pregnancy or postnatally based on a pathognomonic midbrain–hindbrain malformation seen on magnetic resonance imaging brain, which consists of the hypoplasia of the cerebellar vermis, thickened superior cerebellar peduncles, and a deepened interpeduncular fossa described as molar tooth sign. The recurrence rate of JS in the same family is high (25%). In the era of first-trimester anomaly scan, early diagnosis of fetal anomaly is of utmost importance. First-trimester screening or first-trimester scan that is performed from 11 to 13 weeks, 6 days plays an important role in early diagnosis of posterior fossa abnormalities like Blake's pouch cyst, Vermian hypoplasia, Dandy-Walker malformation, and JS and related disorders based on increased intracranial translucency thickness. Our case also shows that early diagnosis of JS can be done by an enlarged intracranial translucency.