Joubert syndrome and related disorders NANDO:2200824 Joubert syndrome and related disorders MEDGEN:1826007 GARD:0019931 MONDO:0015369 Orphanet:140874 NANDO:2100218 Joubert syndrome (JS) and related disorders (JSRD) are a group of developmental delay/multiple congenital anomaly syndromes in which the mandatory feature is the "molar tooth sign'' (MTS), a complex midbrain-hindbrain malformation recognizable on brain imaging. The MTS is characterized by cerebellar vermis hypodysplasia, thickening and malorientation of the superior cerebellar peduncles and abnormally deep interpeduncular fossa. UMLS:C5679612 NANDO:1200661 JSRD autosomal recessive congenital cerebellar ataxia