EDITORVan Royen-Kerkhof et al¹ reported two boys with Gaucher disease type 1 and Joubert syndrome (JS). Their case 1 had, in addition to mental retardation, choreoretinal colobomas, cerebellar vermis agenesis, and abnormal breathing, agenesis of the corpus callosum, hydrocephalus (no further details given), and generalised seizures. Their case 2 had prenatal hydrocephalus and "fulfilled the diagnostic criteria for JS". Information about brain anatomy and retinal findings in case 2 is lacking.

We question the diagnosis of JS in these two patients. The authors cite a 1992 paper² but fail to reference 1997 and 1998 publications that better define the phenotype and characteristic neuroimaging of JS.^3-5 In these most recent publications, the "molar tooth sign" is defined as well as a number of distinct posterior fossa abnormalities not discussed by Van Royen-Kerkhof et al.¹ This is a significant omission because vermis hypoplasia alone is not pathognomonic for JS and can be seen in mimicking . . . [Full text of this article]