Joubert syndrome (JBTS) is an autosomal recessive disorder caused by mutations in at least 35 genes that code for proteins in cilia or the centrosome. JBTS occurs in 1 in every 80-100 thousand live births, however this could be an underestimation due to the heterogeneity of the disease and the overlap of phenotypes with other ciliopathies such as nephronophthisis and Senior-Loken syndrome. Marie Joubert first described the typical phenotype of patients with JBTS in 1968. The hallmark of a JBTS patient is a molar tooth sign on axial brain MRI which is associated with dysmorphic facial features and neurological defects. JBTS can also present with other related diseases (JSRD) of various organ dysfunction such as eye, kidney, liver and skeletal. ARL3 mutations cause JSRD with patients presenting with developmental delay, ataxia, multicystic dysplatic kidney, bilateral renal scarring, recurrent UTIs, and night blindness.
ARL3