The Utility of Next-Generation Sequencing for Identifying the Genetic Basis of Dementia.

The clinical manifestations of dementia are often rapidly matched to a specific clinical syndrome, but the underlying neuropathology is not always obvious. A genetic factor often plays an important role in early onset dementia, but there are cases in which the phenotype has a different genetic basis than is assumed. Two patients, at different times, presented to the Memory Clinic because of memory problems and difficulty in performing daily activities and work. Neither caregiver complained of marked behavioural or personality changes, except for apathy. Patients underwent standard dementia evaluation procedures including clinical symptoms, family history, neuroimaging, neuropsychological evaluation, and genetic analysis of selected genes. Based on specific clinical phenotypes and genetic analysis of selected genes, both patients were diagnosed with frontal variant of Alzheimer's disease. The presence of a rare polymorphism in PSEN2 in both patients allowed the discovery that they belong to the same family. This fact reinforced the belief that there is a strong genetic factor responsible for causing dementia in the family. Next-generation sequencing based on a panel of 118 genes was performed to identify other potential genetic factors that may determine the background of the disease. A mutation in the GRN gene was identified, and the previous diagnosis was changed to frontotemporal dementia. The described cases show how important it is to combine all diagnostic tests available in the diagnostic centre, including new generation genetic tests, in order to establish/confirm the pathological background of clinical symptoms of dementia. If there is any doubt about the final diagnosis, persistent efforts should be made to verify the cause.

Case report on novel mutation in SPAST gene in Polish family with spastic paraplegia.

BACKGROUND: Hereditary spastic paraplegia is a large group of degenerative, neurological disorders characterized by progressive lower limb spasticity and weakness. The disease was investigated precisely but still clinicians often make incorrect or late diagnosis. Our aim was to investigate the genetic background and clinical phenotype of spastic paraplegia in large Polish family. CASE PRESENTATION: A 37 years old woman presented with 4-year history of walking difficulties. On neurological examination, she had signs of upper motor lesion in lower extremities. She denied sphincter dysfunction and her cognition was normal. Her family history was positive for individuals with gait problems. The initial diagnosis was familial spastic paraplegia. Genetic testing identified a novel mutation in SPAST gene. All available family members were examined and had genetic testing. The same mutation in SPAST gene was identified in other affected family members. All patients caring the mutation presented with different phenotypes. CONCLUSION: This study presents a family with spastic paraplegia due to a novel mutation c.1390G>T(p.Glu464Term) in SPAST gene. Affected individuals showed a range of phenotypes that varied in their severity. This case report demonstrates, the signs of hereditary spastic paraplegia can be often misdiagnosed with other diseases. Therefore genetic testing should always be considered in patients with lower limb spasticity and positive family history in order to help to establish the correct diagnosis.

Association between C677T polymorphism of MTHFR gene and risk of amyotrophic lateral sclerosis: Polish population study and a meta-analysis.

OBJECTIVE: Genetic factors play a role in pathogenesis of amyotrophic lateral sclerosis (ALS). A few studies demonstrated that the TT genotype of C677T polymorphism of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene can increase the risk of sporadic ALS. The aim of our study was to determine the relationship between C677T polymorphism of MTHFR gene and the risk of sporadic ALS in Polish population and to perform the meta-analysis assessing the significance this polymorphism for the risk of ALS in Caucasian population. METHODS: We included 251 patients with ALS and 500 control subjects recruited from Polish population and performed the meta-analysis of published data from Caucasian population. MTHFR C677T polymorphism was genotyped using a TaqMan assay and 7900HT Fast real Time PCR System. RESULTS: The frequency of genotypes did not differ significantly between Polish ALS patients and control subjects (CC: 45.0 vs 45.8%, CT: 48.2 vs 45.0%, TT: 6.8 vs 9.2%, P=0.46). The meta-analysis including 863 ALS patients and 1362 controls revealed that TT genotype increases the risk of sporadic ALS in Caucasian population. CONCLUSION: Although we did not find the association between C677T polymorphism of MTHRF gene and risk of ALS in Polish population, the results of meta-analysis suggest that the TT genotype can be a genetic risk factor for ALS in Caucasian population.

Influence of rs1080985 single nucleotide polymorphism of the CYP2D6 gene on response to treatment with donepezil in patients with alzheimer's disease.

BACKGROUND: Recent data indicate that the rs1080985 single nucleotide polymorphism of the cytochrome P450 (CYP) 2D6 gene may affect the response to treatment with donepezil in patients with Alzheimer's disease. There is also evidence that the common apolipoprotein E (APOE) polymorphism may affect the response to treatment with donepezil in Alzheimer's disease. We investigated the association between response to donepezil and the rs1080985 single nucleotide polymorphism, the minor allele (G) of which was previously reported to be associated with a poor response to this drug in patients with Alzheimer's disease. The common APOE polymorphism was also assessed for its relevance to the outcome of this treatment. METHODS: Analysis of CYP2D6 and APOE polymorphisms was undertaken in 88 naive Caucasian patients with Alzheimer's disease. All patients received treatment with donepezil for at least 10 months, and the response to treatment was then assessed according to the National Institute for Health and Clinical Excellence criteria. RESULTS: No significant differences were observed in distribution of the CYP2D6 rs1080985 single nucleotide polymorphism or common APOE polymorphism between responders (68.2%) and nonresponders (31.8%) to treatment with donepezil. CONCLUSION: Our results suggest that neither the CYP2D6 nor the APOE polymorphism influences the response to treatment with donepezil in a Polish population with Alzheimer's disease.

Lack of association of CR1, PICALM and CLU gene polymorphisms with Alzheimer disease in a Polish population.

BACKGROUND AND PURPOSE: Recent genome-wide association studies have indicated 3 new susceptibility loci for Alzheimer disease (AD): complement receptor 1 (CR1), clusterin (CLU), and the phosphatidylinositol-binding clathrin assembly protein (PICALM). We investigated the influence of the rs6656401 single nucleotide polymorphisms (SNP) of the CR1 gene, the rs3851179 SNP of the PICALM gene, and the rs11136000 SNP of the CLU gene on risk of AD in a Polish population. MATERIAL AND METHODS: In 253 Caucasian AD patients and 240 controls, analyses identifying the rs6656401, rs3851179 and rs11136000 SNPs and APOE common polymorphisms were performed. RESULTS: No significant differences were observed in the distribution of the rs6656401 of CR1, rs3851179 of PICALM and rs11136000 of CLU SNPs between AD patients and controls. The APOE ε4 common polymorphism was strongly re-lated to the risk of AD. CONCLUSION: Our results suggest that investigated SNPs are not associated with AD in a Polish population.

[Association of apoE polymorphism and treatment outcome in patients with traumatic brain injury]. / Badanie wplywu polimorfizmu apo E na wynik leczenia chorych z urazami czaszkowo-mózgowymi.

A number of papers published in recent years indicate the importance of the apolipoprotein E gene (apoE) for the outcome of traumatic brain injury [TBI]. A majority of publications suggest that the presence of an epsilon 4 allele is associated with an unfavorable long-term outcome. A hypothesis has been recently posed that this phenomenon may be related to an increased risk of traumatic hypoxic brain damage or post-traumatic ischemic complications. The study group consisted of 95 consecutive TBI patients treated in the years 2000-2001 in the Neurotraumatology Clinic. The presence of apoE epsilon 4 was found in 16 cases. In the statistical analysis relationship was sought between the patient's age and state of consciousness at admission as assessed using the Glasgow Coma Scale, on the one hand, and on the other hand, treatment outcome at 6 months from injury, in patients differing in respect of apoE epsilon 4 presence. Although the number of apoE-negative patients was nearly five times as large as that of the apoE-positive, regression coefficients in both groups were statistically significant. The obtained results indicate that the presence of apoE epsilon 4 contributes to a less favorable clinical TBI outcome than the absence of this allele.

Calpain 10 gene polymorphisms and the risk of ischaemic stroke in a Polish population.

Experimental studies showed that calpain inhibitors suppressed post-ischaemic changes in the brain. We examined whether an association exists between variants of three single nucleotide polymorphisms (SNPs) -43, -19, and -63 in the calpain 10 gene and either stroke or size of ischaemic lesions on the CT in a Polish population. We included 209 patients with a first ischaemic stroke and 148 controls. The patients were divided into four groups based on the infarct size assessed on the CT taken within two week after stroke. Alleles of SNP19 were determined by electrophoresis of the PCR product on agarose gel by size; while for SNP43 and -63 the RFLP method was used. The allele frequencies for patients and controls were similar in both groups: SNP43- G/A- 73.5%/26.5% vs. 71.0%/29%, SNP19-three 32 bp/two 32 bp repeats--65.7%/34.2% vs. 62.2%/37.7%; SNP63- C/T- 89.5%/10.5% vs. 90.9%/9.1%, respectively. The distribution of the genotypes, haplotypes, and haplotype combinations did not differ in both groups. The distribution in the subgroups of patients based on the size of the ischaemic lesions was similar to controls. Our study did not showed any association between calpain 10 SNPs: -43, -19, and -63 and ischaemic stroke, or with the size of post-ischaemic cerebral lesions in a Polish population.