The p.Asp211Gly homozygous HYLS1 mutation is so far known to cause only hydrolethalus syndrome, a lethal malformation syndrome. We report living sibling patients with a homozygous no-stop mutation in exon 4 of HYLS1, NM_145014.2:c.900A>C (p.Ter300TyrextTer11) in the second decade of life. The proband has Joubert syndrome (JS). The younger brother also has JS and an enlarged posterior fossa that was initially diagnosed as Dandy-Walker malformation. The present mutation is unique as it affects the stop codon. The product protein HYLS1 plays an essential role in the formation of the primary cilium. This report provides insight into the spectrum of disorders involving midline brain defects closely related to cilium dysfunction or ciliopathy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.