With the forthcoming identification of the gene targets that trigger Purkinje cell death in the robotic cerebellum, and the functional conservation among the ALF proteins, the robotic mouse promises to deliver important insights into the pathogenesis of human ataxia, but also of mental retardation to which FMR2 and LAF4 have been linked.
Reverse transcriptase PCR studies on the FMR2 and FMR3 genes showed that only the FMR3 gene transcription was abolished, suggesting a possible causal relationship between the lack of FMR3 expression and mental retardation in this patient.
The presence of a phenotypically normal male with absent FMR2 expression in fibroblasts suggests that the relationship between the FRAXE mutation, FMR2 expression and MR needs to be further investigated.
This review summarises the new data on FRAXE associated mental retardation and the FMR2 gene in the light of the recent discoveries of new genes responsible for other forms of non-specific X-linked mental retardation.
We examined the prevalence of the fragile X mental retardation (FMR1) full mutation and fragile X E mutation (FMR2) among preschoolers evaluated for language delay.
Expansion of a (CCG)n repeat in the FMR2 gene corresponds to the FRAXE fragile site which lies distal to FRAXA and is also associated with mental retardation, but it is less frequent and lacks a consistent phenotype.
These results suggest that neither the FMR1 nor the FMR2 mutation is a common etiology of academic failure among school-age children without mental retardation and that the prevalence of the FMR1 premutation is no more frequent in children with academic failure than it is in the general population.