Clinical and molecular characteristics of tectonic (TCTN1) gene-related Joubert syndrome in a Saudi boy.

Joubert syndrome (OMIM:609863) is a hereditary disorder characterized by hypotonia, developmental delay, and a distinctive cerebellar and brain stem malformation known as the molar tooth sign. Variants in tectonic genes TCTN1-3 have been described in a few patients with Joubert syndrome. Furthermore, Joubert syndrome attributed to variants in the TCTN1 (NM_001082538.2) gene has been only described in two reports. This report expands the clinical variability and molecular characterization of an emerging novel causative gene for Joubert syndrome in a Saudi boy born to non-consanguineous marriage with a c.1418del p.(Pro473Leufs*42) and c.800A > G p.(Tyr267Cys) representing a novel compound heterozygous variant of the TCTN1 gene identified by whole-exome sequencing and confirmed by Sanger sequencing. This is the first report of compound heterozygous Joubert syndrome type 13 from Saudi Arabia.