NeuroArray: A Customized aCGH for the Analysis of Copy Number Variations in Neurological Disorders.

BACKGROUND: Neurological disorders are a highly heterogeneous group of pathological conditions that affect both the peripheral and the central nervous system. These pathologies are characterized by a complex and multifactorial etiology involving numerous environmental agents and genetic susceptibility factors. For this reason, the investigation of their pathogenetic basis by means of traditional methodological approaches is rather arduous. High-throughput genotyping technologies, including the microarray-based comparative genomic hybridization (aCGH), are currently replacing classical detection methods, providing powerful molecular tools to identify genomic unbalanced structural rearrangements and explore their role in the pathogenesis of many complex human diseases. METHODS: In this report, we comprehensively describe the design method, the procedures, validation, and implementation of an exon-centric customized aCGH (NeuroArray 1.0), tailored to detect both single and multi-exon deletions or duplications in a large set of multi- and monogenic neurological diseases. This focused platform enables a targeted measurement of structural imbalances across the human genome, targeting the clinically relevant genes at exon-level resolution. CONCLUSION: An increasing use of the NeuroArray platform may offer new insights in investigating potential overlapping gene signatures among neurological conditions and defining genotype-phenotype relationships.

Copy Number Variants in Alzheimer's Disease.

Alzheimer's disease (AD) is a devastating disease mainly afflicting elderly people, characterized by decreased cognition, loss of memory, and eventually death. Although risk and deterministic genes are known, major genetics research programs are underway to gain further insights into the inheritance of AD. In the last years, in particular, new developments in genome-wide scanning methodologies have enabled the association of a number of previously uncharacterized copy number variants (CNVs, gain or loss of DNA) in AD. Because of the exceedingly large number of studies performed, it has become difficult for geneticists as well as clinicians to systematically follow, evaluate, and interpret the growing number of (sometime conflicting) CNVs implicated in AD. In this review, after a brief introduction of this type of structural variation, and a description of available databases, computational analyses, and technologies involved, we provide a systematic review of all published data showing statistical and scientific significance of pathogenic CNVs and discuss the role they might play in AD.

Genetic associations of Nrf2-encoding NFE2L2 variants with Parkinson's disease - a multicenter study.

BACKGROUND: The transcription factor Nrf2, encoded by the NFE2L2 gene, is an important regulator of the cellular protection against oxidative stress. Parkinson's disease is a neurodegenerative disease highly associated with oxidative stress. In a previously published study, we reported associations of NFE2L2 haplotypes with risk and age at onset of idiopathic Parkinson's disease in a Swedish discovery material and a Polish replication material. Here, we have extended the replication study and performed meta-analyses including the Polish material and four new independent European patient-control materials. Furthermore, all SNPs included in the haplotype windows were investigated individually for associations with Parkinson's disease in meta-analyses including all six materials. METHODS: Totally 1038 patients and 1600 control subjects were studied. Based on previous NFE2L2 haplotype associations with Parkinson's disease, five NFE2L2 tag SNPs were genotyped by allelic discrimination and three functional NFE2L2 promoter SNPs were genotyped by sequencing. The impact of individual SNPs and haplotypes on risk and age at onset of Parkinson's disease were investigated in each material individually and in meta-analyses of the obtained results. RESULTS: Meta-analyses of NFE2L2 haplotypes showed association of haplotype GAGCAAAA, including the fully functional promoter haplotype AGC, with decreased risk (OR = 0.8 per allele, p = 0.012) and delayed onset (+1.1 years per allele, p = 0.048) of Parkinson's disease. These results support the previously observed protective effect of this haplotype in the first study. Further, meta-analyses of the SNPs included in the haplotypes revealed four NFE2L2 SNPs associated with age at onset of Parkinson's disease (rs7557529 G > A, -1.0 years per allele, p = 0.042; rs35652124 A > G, -1.1 years per allele, p = 0.045; rs2886161 A > G, -1.2 years per allele, p = 0.021; rs1806649 G > A, +1.2 years per allele, p = 0.029). One of these (rs35652124) is a functional SNP located in the NFE2L2 promoter. No individual SNP was associated with risk of Parkinson's disease. CONCLUSION: Our results support the hypothesis that variation in the NFE2L2 gene, encoding a central protein in the cellular protection against oxidative stress, may contribute to the pathogenesis of Parkinson's disease. Functional studies are now needed to explore these results further.

Potential involvement of GRIN2B encoding the NMDA receptor subunit NR2B in the spectrum of Alzheimer's disease.

Increasing evidence links dysregulation of NR2B-containing N-methyl-D-aspartate receptor remodelling and trafficking to Alzheimer's disease (AD). This theme offers the possibility that the GRIN2B gene, encoding this selective NR2B subunit, represents a potential molecular modulating factor for this disease. Based on this hypothesis, we carried out a mutation scanning of exons and flanking regions of GRIN2B in a well-characterized cohort of AD patients, recruited from Southern Italy. A "de novo" p.K1293R mutation, affecting a highly conserved residue of the protein in the C-terminal domain, was observed for the first time in a woman with familial AD, as the only genetic alteration of relevance. Moreover, an association study between the other detected sequence variants and AD was performed. In particular, the study was focused on five identified single nucleotide polymorphisms: rs7301328, rs1805482, rs3026160, rs1806191 and rs1806201, highlighting a significant contribution from the GRIN2B rs1806201 T allele towards disease susceptibility [adjusted odds ratio (OR) = 1.92, 95% confidence interval (CI) 1.40-2.63, p < 0.001, after correction for sex, age, and APOE ε4 genotype]. This was confirmed by haplotype analysis that identified a specific haplotype, carrying the rs1806201 T allele (CCCTC), over-represented in patients versus controls (adjusted OR = 6.03; p < 0.0001). Although the pathogenic role of the GRIN2B-K1293R mutation in AD is not clear, our data advocate that genetic variability in the GRIN2B gene, involved in synaptic functioning, might provide valuable insights into disease pathogenesis, continuing to attract significant attention in biomedical research on its genetic and functional role.

A multicenter study of glucocerebrosidase mutations in dementia with Lewy bodies.

IMPORTANCE: While mutations in glucocerebrosidase (GBA1) are associated with an increased risk for Parkinson disease (PD), it is important to establish whether such mutations are also a common risk factor for other Lewy body disorders. OBJECTIVE: To establish whether GBA1 mutations are a risk factor for dementia with Lewy bodies (DLB). DESIGN We compared genotype data on patients and controls from 11 centers. Data concerning demographics, age at onset, disease duration, and clinical and pathological features were collected when available. We conducted pooled analyses using logistic regression to investigate GBA1 mutation carrier status as predicting DLB or PD with dementia status, using common control subjects as a reference group. Random-effects meta-analyses were conducted to account for additional heterogeneity. SETTING: Eleven centers from sites around the world performing genotyping. PARTICIPANTS: Seven hundred twenty-one cases met diagnostic criteria for DLB and 151 had PD with dementia. We compared these cases with 1962 controls from the same centers matched for age, sex, and ethnicity. MAIN OUTCOME MEASURES: Frequency of GBA1 mutations in cases and controls. RESULTS We found a significant association between GBA1 mutation carrier status and DLB, with an odds ratio of 8.28 (95% CI, 4.78-14.88). The odds ratio for PD with dementia was 6.48 (95% CI, 2.53-15.37). The mean age at diagnosis of DLB was earlier in GBA1 mutation carriers than in noncarriers (63.5 vs 68.9 years; P < .001), with higher disease severity scores. CONCLUSIONS AND RELEVANCE: Mutations in GBA1 are a significant risk factor for DLB. GBA1 mutations likely play an even larger role in the genetic etiology of DLB than in PD, providing insight into the role of glucocerebrosidase in Lewy body disease.

Spinocerebellar ataxia type 7: report of a new Italian family.

Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disorder characterized by degeneration of the cerebellum, brainstem and retina. We herein describe a family from southern Italy whose proband was a 49-year-old man presenting with ataxia with progressive gait disturbances, clumsiness and visual impairment. A molecular analysis identified 38 cytosine-adenine-guanine (CAG) repeat expansions within the SCA7 gene. Our study confirms the marked anticipation previously observed in SCA7 and extends the small number of patients studied thus far. In this family, the disease is most likely caused by a de novo expansion of a premutated intermediate allele carried by one parent.

Association study between four polymorphisms in the HFE, TF and TFR genes and Parkinson's disease in southern Italy.

Iron overload may lead to neurodegenerative disorders such as Parkinson's disease (PD) and alterations of iron-related genes might be involved in the pathogenesis of this disease. The gene of haemochromatosis (HFE) encodes the HFE protein which interacts with the transferrin receptor (TFR), lowering its affinity for iron-bound transferrin (TF). We examined four known polymorphisms, C282Y and H63D in the HFE gene, G258S in the TF gene and S82G in the TFR gene, in 181 sporadic PD patients and 180 controls from Southern Italy to investigate their possible role in susceptibility to PD. No significant differences were found in genotype and allele frequencies between PD and controls for all the polymorphisms studied, suggesting that these variants do not contribute significantly to the risk of PD.

Lack of association between G-protein coupled receptor kinase 5 gene and Parkinson's disease.

The major component of Lewy Bodies (LB), the pathological hallmark of Parkinson's disease (PD) is α-synuclein, most prominently phosphorylated at serine 129. G-protein coupled receptor kinase 5 (GRK5) has been reported to phosphorylate α-synuclein in vitro, enhancing the α-synuclein toxicity to dopaminergic neurons in Drosophila model. Moreover, GRK5 was found in LBs from brain of PD patients. A genetic association study performed in the Japanese population revealed haplotypic association of the GRK5 gene with susceptibility to sporadic PD. We aimed at investigating whether four polymorphisms within the GRK5 gene (rs871196, rs2420616, rs7069375, rs4752293) could represent a risk factor for sporadic PD in Southern Italy. We genotyped 446 patients with PD and 450 controls for these markers and did not find any significant association with the disease at allelic, genotypic and haplotypic level. Our results indicate that the GRK5 gene does not confer risk to sporadic PD in our sample from Southern Italy.

Single nucleotide polymorphism in the MMP-9 gene is associated with susceptibility to develop multiple sclerosis in an Italian case-control study.

To investigate the role of the matrix metalloproteinase-9 gene (MMP-9) in multiple sclerosis (MS), we analyzed the functional -1562C/T and -90 (CA)(n) repeat polymorphisms in 243 Italian patients with MS and 173 healthy controls. A significant increase of the -1562T allele carriers was found in patients with MS compared to controls. Moreover, haplotype analysis showed that the haplotype formed by the -1562T allele and the L allele ((CA)(

Myocardial (123)I-MIBG scintigraphy for differentiation of Lewy bodies disease from FTD.

Clinical distinction between Lewy bodies disease (LBD) and frontotemporal dementia (FTD) is sometimes difficult. Nigrostriatal dopaminergic degeneration occurs in both LBD and FTD, limiting helpfulness of DAT imaging to differentiate these forms of dementia. Several studies have emphasized the usefulness of myocardial scintigraphy with (123)Metaiodobenzylguanidine ((123)I-MIGB) in assessing the sympathetic nerve terminals in LBD demonstrating that cardiac (123)I-MIGB uptake is decreased in patients with this disease. We investigated the role of cardiac (123)I-MIBG scintigraphy in differentiating patients with LBD from those with FTD. Clinical diagnosis of LBD and FTD was determined according to established consensus criteria. Nine patients with LBD (1 possible and 8 probable), 6 patients with FTD, and 16 control subjects were involved in the study. The heart to mediastinum ratio (H/M) of (123)I-MIBG uptake was markedly reduced in all patients with LBD (H/M early: 1.25±0.12; delayed: 1.14±0.13) whereas it was normal in patients with FTD (H/M early: 1.86±0.20; delayed: 1.80±0.23) and in controls (H/M early: 1.91±0.17; delayed: 1.99±0.19), suggesting that cardiac (123)I-MIBG scintigraphy can help distinguish patients with LBD from those with FTD.

Chronic bilateral subthalamic deep brain stimulation in a patient with homozygous deletion in the parkin gene.

Chronic subthalamic nucleus deep brain stimulation (STN-DBS) is an efficacious treatment for idiopathic Parkinson's disease (PD) that cannot be further improved by medical therapy. We present a case of an individual with juvenile parkinsonism caused by homozygous deletion of exon 3 in the parkin gene with disabling long-term side-effects from levodopa who underwent bilateral STN neuromodulation. Parkin-linked parkinsonism may show clinical features different from sporadic PD, yet it shares levodopa responsiveness. Because levodopa responsiveness is a predictor of STN-DBS efficacy, we argued that this kind of surgical approach might be efficacious in hereditary parkin-linked juvenile parkinsonism. We evaluated clinical and functional assessment before and 12 months after surgery. The results showed that the Unified Parkinson Disease Rating Scales Motor score improved by 84% in our patient, the levodopa equivalent daily dose medication (LEDD) was reduced by 66%, and, finally, disabling and severe dyskinesias disappeared.