Prevalence And Characterisation Of FMR1 Gene's Premutation Carriers Amongst Older Males Presenting With Tremor/ataxia
Funder
National Health and Medical Research Council
Funding Amount
$199,450.00
Summary
The study concerns a novel form of progressive neurological disorder associated with tremor and body imbalance occurring in older males and caused by a small expansion of the trinucleotide (CGG) repeat in a fragile X (FMR1) gene. This expansion is termed 'premutation', in contrast with the full mutation, where a large expansion of the CGG repeat in this gene causes Fragile X Syndrome, a common form of intellectual disability. While brain anomaly in the full mutation is caused by a deficit of the ....The study concerns a novel form of progressive neurological disorder associated with tremor and body imbalance occurring in older males and caused by a small expansion of the trinucleotide (CGG) repeat in a fragile X (FMR1) gene. This expansion is termed 'premutation', in contrast with the full mutation, where a large expansion of the CGG repeat in this gene causes Fragile X Syndrome, a common form of intellectual disability. While brain anomaly in the full mutation is caused by a deficit of the FMR1 specific protein product (FMRP), the pathways from premutation to a neurological disorder are unknown. In this disorder, neurological dysfunction is associated with brain atrophy visible in magnetic resonance (MRI) images. Molecular studies showed increased levels of 'messenger' RNA (mRNA), which indicates overexpression of FMR1 gene . Our own study showed significantly increased (41.7%) prevalence of neurological involvement in male premutation carriers aged >50, compared with age-matched norms. Moreover, a screening of patients with two neurological disorders associated with tremor showed a significant increase of premutation carriers (5%- 22%). The aim of this study is to test hypotheses about the association of late-onset neurological disorders of unknown cause presenting tremor and imbalance, with a fragile X premutation in males, by screening for the presence of this premutation; and then conducting a full assessment of the identified premutation carriers, including detailed neurological, neuropsychological and MRI tests, to establish the spectrum of neurological involvement. This involvement will be correlated with the molecular (DNA, mRNA, FMRP) findings. The results will contribute to understanding the mechanisms of neurological involvement caused by this premutation. Moreover, estimation of the prevalence of this premutation in relevant neurological disorders will impact on standard diagnostic, and possibly future treatment approaches in neurology clinics.Read moreRead less
Functional Significance Of MeCP2 Target Genes In The Pathogenesis Of Rett Syndrome.
Funder
National Health and Medical Research Council
Funding Amount
$476,815.00
Summary
Rett syndrome (RTT) is a devastating progressive disorder affecting motor and intellectual development. It is characterised by normal development for the first 6-12 months of life, followed by developmental regression with the loss of learned purposeful hand function, loss of acquired speech and communicative abilities, sometimes leading to the incorrect diagnosis of autism. It is a genetic disorder and contributes to a substantial proportion of girls with severe mental retardation. In 1999, a g ....Rett syndrome (RTT) is a devastating progressive disorder affecting motor and intellectual development. It is characterised by normal development for the first 6-12 months of life, followed by developmental regression with the loss of learned purposeful hand function, loss of acquired speech and communicative abilities, sometimes leading to the incorrect diagnosis of autism. It is a genetic disorder and contributes to a substantial proportion of girls with severe mental retardation. In 1999, a gene (called MECP2) was identified which appears to be the cause of RTT in at least 80% of affected girls and women. Now that the gene responsible for many cases of RTT has been found, new questions are being asked. Why are the effects of these mutations restricted to the brain? Which other genes might play a role in the symptoms seen in RTT? The focus of this research project is to examine these 2 questions. Using new research techniques, we have identified genes that are themselves secondarily affected by mutations in the MECP2 gene. We wish to study these genes in more detail, with the aim being to gain a greater understanding of how these genes contribute to the onset of impaired brain function in girls and women with RTT. These insights are essential foundations for the development and evaluation of new and more specific therapies for this as yet incurable disorder.Read moreRead less
STK9, A Second Rett Syndrome Gene: Genetic And Functional Studies
Funder
National Health and Medical Research Council
Funding Amount
$468,750.00
Summary
Rett syndrome (RTT) is a devastating progressive disorder affecting motor and intellectual development. It is characterised by normal development for the first 6-12 months of life, followed by developmental regression with the loss of learned purposeful hand function, loss of acquired speech and communicative abilities, sometimes leading to the incorrect diagnosis of autism. It may be the most common cause of progressive mental retardation in girls, with an estimated prevalence in Australia of 1 ....Rett syndrome (RTT) is a devastating progressive disorder affecting motor and intellectual development. It is characterised by normal development for the first 6-12 months of life, followed by developmental regression with the loss of learned purposeful hand function, loss of acquired speech and communicative abilities, sometimes leading to the incorrect diagnosis of autism. It may be the most common cause of progressive mental retardation in girls, with an estimated prevalence in Australia of 1 per 10,000 females under the age of twelve years. It is a genetic disorder and occurs almost exclusively in females. In 1999, a gene (called MECP2) was identified which appears to be the cause of RTT in most girls and women with RTT. However, for 5 - 10% of RTT subjects, no gene change is found in the MECP2 gene, raising the possibility that other genes may also be responsible for RTT. Our research group has identified one of these genes. Known as STK9, little is known about this gene's function. Of great interest is the fact that our studies suggest that STK9 could also be a caus of intellectual disability in other patients, and with autism. The focus of this research project is to explore how common gene changes in STK9 are in a large number of children with RTT, intellectual disability and seizures, and autism with intellectual disability and seizures. Using cutting edge research technology, we will go on to study how STK9 interacts with MECP2 and other genes, in order to better understand how these genes may be detrimentally affecting brain function in girls and women with Rett syndrome and other neurological disorders. These studies will give us a greater understanding of normal brain development and function.Read moreRead less