Reduced neuronal size and mTOR pathway activity in the Mecp2 A140V Rett syndrome mouse model.

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutation in the X-linked gene, encoding methyl-CpG-binding protein 2. We have created a mouse model ( A140V "knock-in" mutant) expressing the recurrent human A140V mutation linked to an X-linked mental retardation/Rett syndrome phenotype. Morphological analyses focused on quantifying soma and nucleus size were performed on primary hippocampus and cerebellum granule neuron (CGN) cultures from mutant ( ) and wild type ( ) male mice.

Skewed allele-specific expression of the NF1 gene in normal subjects: a possible mechanism for phenotypic variability in neurofibromatosis type 1.

Neurofibromatosis type 1 is an autosomal dominant disorder characterized by neurocutaneous abnormalities, learning disabilities, and attention-deficit disorder. Neurofibromatosis type 1 symptom severity can be highly variable even within families where all affected members carry the same mutation. We hypothesized that variation in the expression of the normal NF1 allele may be a mechanism that participates in producing variable phenotypes.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay: compound heterozygotes for nonsense mutations of the SACS gene.

Mutations of the SACS gene have been reported in patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay from Canada (Quebec), Tunisia, Japan, Turkey, Belgium, Italy, Spain, the Netherlands, and Germany. Features that distinguish autosomal recessive spastic ataxia of Charlevoix-Saguenay from other recessive ataxias include sensory motor polyneuropathy and hypermyelinated retinal nerve fibers. We describe the clinical, electrophysiological, and radiological features in 2 white American siblings diagnosed with autosomal recessive spastic ataxia of Charlevoix-Saguenay.

Evidence for population variation in TSC1 and TSC2 gene expression.

Background: Tuberous sclerosis complex (TSC) is an autosomal dominant neurogenetic disorder caused by mutations in one of two genes, TSC1 or TSC2, which encode the proteins hamartin and tuberin, respectively 123. Common features of TSC include intractable epilepsy, mental retardation, and autistic features. TSC is associated with specific brain lesions, including cortical tubers, subependymal nodules and subependymal giant cell astrocytomas.

Abnormalities of cell packing density and dendritic complexity in the MeCP2 A140V mouse model of Rett syndrome/X-linked mental retardation.

Background: Rett syndrome (RTT), a common cause of mental retardation in girls, is associated with mutations in the MECP2 gene. Most human cases of MECP2 mutation in girls result in classical or variant forms of RTT. When these same mutations occur in males, they often present as severe neonatal encephalopathy.