The Gly2019Ser mutation in LRRK2 is not fully penetrant in familial Parkinson's disease: the GenePD study

<p>Abstract</p> <p>Background</p> <p>We report age-dependent penetrance estimates for leucine-rich repeat kinase 2 (<it>LRRK2</it>)-related Parkinson's disease (PD) in a large sample of familial PD. The most frequently seen <it>LRRK2 </it>mutation, Gly2019Ser (G2019S), is associated with approximately 5 to 6% of familial PD cases and 1 to 2% of idiopathic cases, making it the most common known genetic cause of PD. Studies of the penetrance of <it>LRRK2 </it>mutations have produced a wide range of estimates, possibly due to differences in study design and recruitment, including in particular differences between samples of familial PD versus sporadic PD.</p> <p>Methods</p> <p>A sample, including 903 affected and 58 unaffected members from 509 families ascertained for having two or more PD-affected members, 126 randomly ascertained PD patients and 197 controls, was screened for five different <it>LRRK2 </it>mutations. Penetrance was estimated in families of <it>LRRK2 </it>carriers with consideration of the inherent bias towards increased penetrance in a familial sample.</p> <p>Results</p> <p>Thirty-one out of 509 families with multiple cases of PD (6.1%) were found to have 58 <it>LRRK2 </it>mutation carriers (6.4%). Twenty-nine of the 31 families had G2019S mutations while two had R1441C mutations. No mutations were identified among controls or unaffected relatives of PD cases. Nine PD-affected relatives of G2019S carriers did not carry the <it>LRRK2 </it>mutation themselves. At the maximum observed age range of 90 to 94 years, the unbiased estimated penetrance was 67% for G2019S families, compared with a baseline PD risk of 17% seen in the non-<it>LRRK2</it>-related PD families.</p> <p>Conclusion</p> <p>Lifetime penetrance of <it>LRRK2 </it>estimated in the unascertained relatives of multiplex PD families is greater than that reported in studies of sporadically ascertained <it>LRRK2 </it>cases, suggesting that inherited susceptibility factors may modify the penetrance of <it>LRRK2 </it>mutations. In addition, the presence of nine PD phenocopies in the <it>LRRK2 </it>families suggests that these susceptibility factors may also increase the risk of non-<it>LRRK2</it>-related PD. No differences in penetrance were found between men and women, suggesting that the factors that influence penetrance for <it>LRRK2 </it>carriers are independent of the factors which increase PD prevalence in men.</p

Intrinsic Reward Motivates Large-Scale Shifts Between Cognitive Control and Default Mode Networks During Task Performance

Cognitive control is an important framework for understanding the neuropsychological processes that underlie and enable the successful completion of everyday tasks. Only recently has research in this area investigated motivational contributions to control allocation. An important gap in our understanding is the way in which intrinsic rewards associated with a task motivate the sustained allocation of cognitive control. In three behavioral and one functional magnetic resonance imaging studies, we use a naturalistic and open-sourced simulator to show that changes in the balance between task difficulty and an individual’s ability to perform the task result in different levels of intrinsic reward, which motivates dynamic shifts between networked brain states. Specifically, high levels of intrinsic reward associated with a balance between task difficulty and individual ability are associated with increased connectivity between cognitive control and reward networks. By comparison, a mismatch between task difficulty and individual ability is associated with lower levels of intrinsic reward and corresponds to increased activity within the default mode network. Insular activation suggests that motivational salience, as defined by the level of intrinsic reward, drives shifts between networked brain states associated with task engagement or disengagement. These results implicate reward processing as a critical component of cognitive control

Replication of association between ELAVL4 and Parkinson disease : the Gene PD study

Genetic variants in embryonic lethal, abnormal vision, Drosophila-like 4 (ELAVL4) have been reported to be associated with onset age of Parkinson disease (PD) or risk for PD affection in Caucasian populations. In the current study we genotyped three single nucleotide polymorphisms in ELAVL4 in a Caucasian study sample consisting of 712 PD patients and 312 unrelated controls from the Gene PD study. The minor allele of rs967582 was associated with increased risk of PD (odds ratio = 1.46, nominal P value = 0.011) in the Gene PD population. The minor allele of rs967582 was also the risk allele for PD affection or earlier onset age in the previously studied populations. This replication of association with rs967582 in a third cohort further implicates ELAVL4 as a PD susceptibility gene.5 page(s

The Gly2019Ser mutation in LRRK2is not fully penetrant in familial Parkinson's disease: the GenePD study

Abstract Background We report age-dependent penetrance estimates for leucine-rich repeat kinase 2 (LRRK2)-related Parkinson's disease (PD) in a large sample of familial PD. The most frequently seen LRRK2 mutation, Gly2019Ser (G2019S), is associated with approximately 5 to 6% of familial PD cases and 1 to 2% of idiopathic cases, making it the most common known genetic cause of PD. Studies of the penetrance of LRRK2 mutations have produced a wide range of estimates, possibly due to differences in study design and recruitment, including in particular differences between samples of familial PD versus sporadic PD. Methods A sample, including 903 affected and 58 unaffected members from 509 families ascertained for having two or more PD-affected members, 126 randomly ascertained PD patients and 197 controls, was screened for five different LRRK2 mutations. Penetrance was estimated in families of LRRK2 carriers with consideration of the inherent bias towards increased penetrance in a familial sample. Results Thirty-one out of 509 families with multiple cases of PD (6.1%) were found to have 58 LRRK2 mutation carriers (6.4%). Twenty-nine of the 31 families had G2019S mutations while two had R1441C mutations. No mutations were identified among controls or unaffected relatives of PD cases. Nine PD-affected relatives of G2019S carriers did not carry the LRRK2 mutation themselves. At the maximum observed age range of 90 to 94 years, the unbiased estimated penetrance was 67% for G2019S families, compared with a baseline PD risk of 17% seen in the non-LRRK2-related PD families. Conclusion Lifetime penetrance of LRRK2 estimated in the unascertained relatives of multiplex PD families is greater than that reported in studies of sporadically ascertained LRRK2 cases, suggesting that inherited susceptibility factors may modify the penetrance of LRRK2 mutations. In addition, the presence of nine PD phenocopies in the LRRK2 families suggests that these susceptibility factors may also increase the risk of non-LRRK2-related PD. No differences in penetrance were found between men and women, suggesting that the factors that influence penetrance for LRRK2 carriers are independent of the factors which increase PD prevalence in men

Huntington CAG repeat size does not modify onset age in familial Parkinson's disease : the GenePD study

The ATP/ADP ratio reflects mitochondrial function and has been reported to be influenced by the size of the Huntington disease gene (HD) repeat. Impaired mitochondrial function has long been implicated in the pathogenesis of Parkinson's disease (PD), and therefore, we evaluated the relationship of the HD CAG repeat size to PD onset age in a large sample of familial PD cases. PD affected siblings (n = 495), with known onset ages from 248 families, were genotyped for the HD CAG repeat. Genotyping failed in 11 cases leaving 484 for analysis, including 35 LRRK2 carriers. All cases had HD CAG repeats (range, 15-34) below the clinical range for HD, although 5.2% of the sample (n = 25) had repeats in the intermediate range (the intermediate range lower limit = 27; upper limit = 35 repeats), suggesting that the prevalence of intermediate allele carriers in the general population is significant. No relation between the HD CAG repeat size and the age at onset for PD was found in this sample of familial PD.6 page(s