Time to generalization and prediction of survival in patients with amyotrophic lateral sclerosis: a retrospective observational study.

BACKGROUND AND PURPOSE: A strong association between time to generalization (TTG), considered as the time of spreading of the clinical signs from spinal or bulbar localization to both, and survival was recently identified in patients with amyotrophic lateral sclerosis (ALS). Thus, TTG may be used as an early to intermediate end-point in survival studies. The aim of the present study was to test TTG as a predictor of survival in ALS. METHODS: This was an observational retrospective study of ALS patients from a tertiary referral centre over a 5-year follow-up period. RESULTS: In 212 ALS patients, TTG was associated with time to death/tracheostomy [R 0.62, 95% confidence interval (CI) 0.53-0.70; P < 0.001]. In a time-to-event analysis, longer TTG resulted in lower risk to reach a composite outcome (death or tracheostomy) both in univariate [hazard ratio (HR) 0.98, 95% CI 0.97-0.99] and multivariate Cox analyses (HR 0.98, 95% CI 0.96-0.99). TTG predicted death/tracheostomy at 4 years (C-statistic 0.58; 95% CI 0.53-0.63) and at 5 years (C-statistic 0.58; 95% CI 0.53-0.62). CONCLUSIONS: Based on the present results from a large clinical cohort, TTG may be used as a new early to intermediate end-point to describe the ALS natural history. TTG may be potentially useful as a new primary outcome measure for clinical trials.

Coffee, tea, and caffeine consumption and prevention of late-life cognitive decline and dementia: a systematic review.

A prolonged preclinical phase of more than two decades before the onset of dementia suggested that initial brain changes of Alzheimer's disease (AD) and the symptoms of advanced AD may represent a unique continuum. Given the very limited therapeutic value of drugs currently used in the treatment of AD and dementia, preventing or postponing the onset of AD and delaying or slowing its progression are becoming mandatory. Among possible reversible risk factors of dementia and AD, vascular, metabolic, and lifestyle-related factors were associated with the development of dementia and late-life cognitive disorders, opening new avenues for the prevention of these diseases. Among diet-associated factors, coffee is regularly consumed by millions of people around the world and owing to its caffeine content, it is the best known psychoactive stimulant resulting in heightened alertness and arousal and improvement of cognitive performance. Besides its short-term effect, some case-control and cross-sectional and longitudinal population-based studies evaluated the long-term effects on brain function and provided some evidence that coffee, tea, and caffeine consumption or higher plasma caffeine levels may be protective against cognitive impairment/decline and dementia. In particular, several cross-sectional and longitudinal population-based studies suggested a protective effect of coffee, tea, and caffeine use against late-life cognitive impairment/decline, although the association was not found in all cognitive domains investigated and there was a lack of a distinct dose-response association, with a stronger effect among women than men. The findings on the association of coffee, tea, and caffeine consumption or plasma caffeine levels with incident mild cognitive impairment and its progression to dementia were too limited to draw any conclusion. Furthermore, for dementia and AD prevention, some studies with baseline examination in midlife pointed to a lack of association, although other case-control and longitudinal population-based studies with briefer follow-up periods supported favourable effects of coffee, tea, and caffeine consumption against AD. Larger studies with longer follow-up periods should be encouraged, addressing other potential bias and confounding sources, so hopefully opening new ways for diet-related prevention of dementia and AD.

Genome-wide haplotype association study identifies the FRMD4A gene as a risk locus for Alzheimer's disease.

Recently, several genome-wide association studies (GWASs) have led to the discovery of nine new loci of genetic susceptibility in Alzheimer's disease (AD). However, the landscape of the AD genetic susceptibility is far away to be complete and in addition to single-SNP (single-nucleotide polymorphism) analyses as performed in conventional GWAS, complementary strategies need to be applied to overcome limitations inherent to this type of approaches. We performed a genome-wide haplotype association (GWHA) study in the EADI1 study (n=2025 AD cases and 5328 controls) by applying a sliding-windows approach. After exclusion of loci already known to be involved in AD (APOE, BIN1 and CR1), 91 regions with suggestive haplotype effects were identified. In a second step, we attempted to replicate the best suggestive haplotype associations in the GERAD1 consortium (2820 AD cases and 6356 controls) and observed that 9 of them showed nominal association. In a third step, we tested relevant haplotype associations in a combined analysis of five additional case-control studies (5093 AD cases and 4061 controls). We consistently replicated the association of a haplotype within FRMD4A on Chr.10p13 in all the data set analyzed (OR: 1.68; 95% CI: (1.43-1.96); P=1.1 × 10(-10)). We finally searched for association between SNPs within the FRMD4A locus and Aß plasma concentrations in three independent non-demented populations (n=2579). We reported that polymorphisms were associated with plasma Aß42/Aß40 ratio (best signal, P=5.4 × 10(-7)). In conclusion, combining both GWHA study and a conservative three-stage replication approach, we characterised FRMD4A as a new genetic risk factor of AD.

Interacting with γ-secretase for treating Alzheimer's disease: from inhibition to modulation.

Drugs currently used for the treatment of Alzheimer's disease (AD) produce limited clinical benefits, and there is no disease-modifying therapy yet available. Compounds that inhibit or modulate γ-secretase, the pivotal enzyme that generates ß-amyloid (Aß), are potential therapeutics for AD. This article briefly reviews the profile of γ-secretase inhibitors and modulators that have reached the clinic. Studies in both transgenic and non-transgenic animal models of AD have indicated that γ-secretase inhibitors, administered by the oral route, are able to lower brain Aß concentrations. However, scanty data are available on the effects of these compounds on brain Aß deposition after prolonged administration. γ-Secretase inhibitors may cause abnormalities in the gastrointestinal tract, thymus, spleen, skin, and decrease in lymphocytes and alterations in hair color in experimental animals and in man, effects believed to be associated with the inhibition of the cleavage of Notch, a transmembrane receptor involved in regulating cell-fate decisions. Unfortunately, two large Phase III clinical trials of semagacestat in mild-to-moderate AD patients were prematurely interrupted because of the observation of a detrimental cognitive and functional effect of the drug. These detrimental effects were mainly ascribed to the inhibition of the processing of an unknown substrate of γ-secretase. It has been also hypothesized that the detrimental cognitive effects observed after semagacestat administration are due to the accumulation of the neurotoxic precursor of Aß (the carboxy-terminal fragment of amyloid precursor protein, APP, or CTFß) resulting from the block of the γ-secretase cleavage activity on APP. Some non-steroidal anti-inflammatory drugs and other small organic molecules have been found to modulate γ-secretase shifting its cleavage activity from longer to shorter Aß species without affecting Notch cleavage. However, two large Phase III studies in mild AD patients with tarenflurbil, a putative γ-secretase modulator, were also completely negative. The failure of tarenflurbil was ascribed to low potency and brain penetration. New more selective γ-secretase inhibitors and more potent, more brain penetrant γ-secretase modulators are being developed with the hope of overcoming the previous setbacks. Further understanding of the reasons of the failures of these γ-secretase-based drugs in AD may be important for the future research on effective treatments for this devastating disease.

Different models of frailty in predementia and dementia syndromes.

Dementia is an increasingly common disease in the aging population, and the numbers are expected to rise exponentially in coming years. Therefore, there is a critical need to potentially individualize new strategies able to prevent and to slow down the progression of predementia and dementia syndromes. Despite a substantial increase in the epidemiological and clinical evidence on frailty, there is no consensus on its definition or on what criteria should be used to identify older individuals with frailty. Frailty appears to be a nonspecific state of vulnerability, which reflects multisystem physiological change. In fact, current thinking is that not only physical but also psychological, cognitive and social factors contribute to this multidimensional syndrome and need to be taken into account in its definition and treatment. Cognition has already been considered as a component of frailty, and it has been demonstrated that it is associated with adverse health outcomes. In a recent population-based study, physical frail demented patients were at higher risk of all-cause mortality over 3- and 7-year follow-up periods. Several studies have also reported that physical frailty is associated with low cognitive performance, incidence of Alzheimer's disease (AD), and mild cognitive impairment, and AD pathology in older persons with and without dementia. Most frailty instruments use a dichotomous scoring system classifying a person as either frail or not frail, while a continuous or an ordinal scoring system on multiple levels would be preferable to be used as an outcome measure. Recently, a Multidimensional Prognostic Index (MPI), derived from a standardized comprehensive geriatric assessment, was effective in predicting short- and long-term mortality risk in hospitalized patients with dementia. Overall taken together these findings supported the concept that outcome measures linked to multidimensional impairment may be extremely important in making clinical decisions, especially for monitoring drug treatment in randomized clinical trials also for predementia and dementia syndromes.

Mediterranean diet in predementia and dementia syndromes.

There is a critical need to potentially individualize new strategies able to prevent and to slow down the progression of predementia and dementia syndromes. Only recently higher adherence to a Mediterranean-type diet was associated with decreased cognitive decline although the Mediterranean diet (MeDi) combines several foods, micro- and macronutrients already separately proposed as potential protective factors against dementia and predementia syndromes. In fact, elevated saturated fatty acids could have negative effects on age-related cognitive decline and mild cognitive impairment (MCI). Furthermore, at present, epidemiological evidence suggested a possible association among fish consumption, monounsaturated fatty acids and polyunsaturated fatty acids (PUFA) (particularly, n-3 PUFA) and reduced risk of cognitive decline and dementia. Light to moderate alcohol use may be associated with a reduced risk of incident dementia and Alzheimer's disease (AD), while for vascular dementia, cognitive decline, and predementia syndromes the current evidence is only suggestive of a protective effect. Finally, the limited epidemiological evidence available on fruit and vegetable consumption and cognition generally supported a protective role of these macronutrients against cognitive decline, dementia, and AD. Moreover, recent prospective studies provided evidence that higher adherence to a Mediterranean-type diet could be associated with slower cognitive decline, reduced risk of progression from MCI to AD, reduced risk of AD, and decreased all-causes mortality in AD patients. These findings suggested that adherence to the MeDi may affect not only the risk for AD, but also for predementia syndromes and their progression to overt dementia. Nonetheless, at present, no definitive dietary recommendations are possible. However, high levels of consumption of fats from fish, vegetable oils, non-starchy vegetables, low glycemic fruits, and diet low in foods with added sugars and with moderate wine intake should be encouraged. In fact, this dietary advice is in accordance with recommendations for lowering the risk of cardiovascular disease, obesity, diabetes, and hypertension and might open new ways for the prevention and management of cognitive decline and dementia.

Metabolic syndrome, mild cognitive impairment, and dementia.

At present, the search for preventive strategies for cognitive decline and dementia appears to be of crucial importance, given that the therapeutic options currently available have demonstrated limited efficacy. Cumulative epidemiological evidence suggested that vascular and vascular-related factors may be important for the development of age-related cognitive decline (ARCD), mild cognitive impairment (MCI), and cognitive decline of degenerative (Alzheimer's disease, AD) or vascular origin (vascular dementia, VaD). Among vascular-related factors, metabolic syndrome (MetS) has been associated with the reduced risk of predementia syndromes (ARCD and MCI), overall dementia, and VaD, but contrasting findings also exist on the possible role of MetS in AD. In the next future, trials could then be undertaken to determine if modifications of these risks including inflammation, another factor probably related to MetS, could lower risk of developing cognitive decline. If MetS is associated with increased risk of developing cognitive impairment, then early identification and treatment of these individuals at risk might offer new avenues for disease course modification. Future research aimed at identifying mechanisms that underlie comorbid associations will not only provide important insights into the causes and interdependencies of predementia and dementia syndromes, but will also inspire novel strategies for treating and preventing these disorders. At present, vascular risk factor management could be decisive in delaying the onset of dementia syndromes or in preventing the progression of predementia syndromes.

APOE and Alzheimer disease: a major gene with semi-dominant inheritance.

Apolipoprotein E (APOE) dependent lifetime risks (LTRs) for Alzheimer Disease (AD) are currently not accurately known and odds ratios alone are insufficient to assess these risks. We calculated AD LTR in 7351 cases and 10 132 controls from Caucasian ancestry using Rochester (USA) incidence data. At the age of 85 the LTR of AD without reference to APOE genotype was 11% in males and 14% in females. At the same age, this risk ranged from 51% for APOE44 male carriers to 60% for APOE44 female carriers, and from 23% for APOE34 male carriers to 30% for APOE34 female carriers, consistent with semi-dominant inheritance of a moderately penetrant gene. Using PAQUID (France) incidence data, estimates were globally similar except that at age 85 the LTRs reached 68 and 35% for APOE 44 and APOE 34 female carriers, respectively. These risks are more similar to those of major genes in Mendelian diseases, such as BRCA1 in breast cancer, than those of low-risk common alleles identified by recent GWAS in complex diseases. In addition, stratification of our data by age groups clearly demonstrates that APOE4 is a risk factor not only for late-onset but for early-onset AD as well. Together, these results urge a reappraisal of the impact of APOE in Alzheimer disease.

Towards disease-modifying treatment of Alzheimer's disease: drugs targeting beta-amyloid.

Pathological, genetic, biochemical and pharmacological studies support the hypothesis that brain accumulation of oligomeric species of beta-amyloid (Abeta) peptides may cause Alzheimer's disease (AD). Drugs currently used for the treatment of AD produce limited clinical benefits and do not treat the underlying causes of the disease. In the last 10 years, new therapeutic approaches targeting Abeta have been discovered and developed with the hope of modifying the natural history of the disease. Several active and passive immunotherapy approaches are under investigation in clinical trials with the aim of accelerating Abeta clearance from the brain of the AD patients. The most advanced of these immunological approaches is bapineuzumab, composed of humanized anti-Abeta monoclonal antibodies, that is being tested in two large late-stage trials. Compounds that interfere with proteases regulating Abeta formation from amyloid precursor protein (APP) are also actively pursued. Unfortunately, the most biologically attractive of these proteases, beta-secretase, that regulates the first step of the amyloidogenic APP metabolism, was found to be particularly problematic to block and only one compound (CTS21166) has reached clinical testing so far. Conversely, several inhibitors of gamma-secretase, the protease that regulates the last metabolic step generating Abeta, have been identified, the most advanced being LY-450139 (semagacestat), presently in Phase III clinical development. Compounds that stimulate alpha-secretase, the enzyme responsible for the non-amyloidogenic metabolism of APP, are also being developed one of them, EHT-0202, has recently started a Phase II study. Furthermore, brain penetrant inhibitors of Abeta aggregation have been identified and one of such compounds, PBT-2, has produced encouraging neuropsychological results in a recently completed Phase II study. With all these anti-Abeta approaches in clinical testing, we will know in few years if the Abeta hypothesis of AD is correct.

Effect of a CYP2D6 polymorphism on the efficacy of donepezil in patients with Alzheimer disease.

OBJECTIVE: To evaluate the influence of the single nucleotide polymorphism rs1080985 in the cytochrome P450 2D6 (CYP2D6) gene on the efficacy of donepezil in patients with mild to moderate Alzheimer disease (AD). METHODS: This was a multicenter, prospective cohort study of 127 white patients with AD according to the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association Work Group criteria. Patients were treated with donepezil 5-10 mg/daily for 6 months. Cognitive and functional statuses were evaluated at baseline and at 6-month follow-up. Response to therapy was defined according to the National Institute for Health and Clinical Excellence criteria. Compliance and drug-related adverse events were also evaluated. The analyses identifying the CYP2D6 and APOE polymorphisms were performed in blinded fashion. RESULTS: At 6-month follow-up, 69 of 115 patients (60%) were responders and 46 patients (40%) were nonresponders to donepezil treatment. A significantly higher frequency of patients with the G allele of rs1080985 was found in nonresponders than in responders (58.7% vs 34.8%, p = 0.013). Logistic regression analysis adjusted for age, sex, Mini-Mental State Examination score at baseline, and APOE demonstrated that patients with the G allele had a significantly higher risk of poor response to donepezil treatment (odds ratio 3.431, 95% confidence interval 1.490-7.901). CONCLUSIONS: The single nucleotide polymorphism rs1080985 in the CYP2D6 gene may influence the clinical efficacy of donepezil in patients with mild to moderate Alzheimer disease (AD). The analysis of CYP2D6 genotypes may be useful in identifying subgroups of patients with AD who have different clinical responses to donepezil.

Vascular risk factors, alcohol intake, and cognitive decline.

Since the therapeutic options currently available have demonstrated limited efficacy, the search for preventive strategies for cognitive decline and dementia is mandatory. A possible role of vascular and lifestyle-related factors was recently proposed for age-related changes of cognitive function, predementia syndromes, and cognitive decline of degenerative (Alzheimer's disease, AD) or vascular origin. At present, cumulative evidence suggested that vascular risk factors may be important in the development of mild cognitive impairment (MCI), dementia, and AD. Among vascular-related factors, metabolic syndrome has been associated with the risk of cognitive decline and overall dementia. Moderate alcohol drinking has been proposed as a protective factor against MCI and dementia in several longitudinal studies, but contrasting findings also exist. However, in most cases, these were only observational studies, and results are awaited from large multicenter randomized clinical trials in older persons. At present, vascular risk factor management, lifestyle changes, and drugs could be employed together to delay the onset of dementia syndromes.

Dietary fatty acids, age-related cognitive decline, and mild cognitive impairment.

Currently available epidemiological evidence suggested that an increase of saturated fatty acids (SFA) could have negative effects on cognitive functions, while increased polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) may be protective against cognitive decline. In a Southern Italian elderly population from the Italian Longitudinal Study on Aging (ILSA), a clear reduction of risk of age-related cognitive decline (ARCD) has been found with elevated intake of PUFA and MUFA. Furthermore, in the ILSA, while dietary fatty acids intakes were not associated with incident mild cognitive impairment (MCI), high PUFA intake appeared to have borderline non-significant trend for a protective effect against the development of MCI. These epidemiological findings on predementia syndromes, i.e. MCI or ARCD, together with a recent randomised controlled trial on a possible effect on cognitive and depressive symptoms of omega-3 PUFA supplementation in patients with very mild AD, suggested a possible role of fatty acids intake in maintaining adequate cognitive functioning and possibly in preventing or delaying the onset of dementia.

Codon 129 polymorphism of prion protein gene in sporadic Alzheimer's disease.

Codon 129 polymorphism of the prion protein gene represents a major genetic risk factor for Creutzfeldt-Jakob disease (CJD). Both CJD and Alzheimer's disease (AD) are brain amyloidoses and it would be possible that codon 129 polymorphism plays a role in the susceptibility to AD. In order to investigate this polymorphism in AD the distribution of polymorphic codon 129 of the PRNP gene in 194 probable AD and 124 controls selected in Italy and 109 neuropathologically verified AD and 58 matched controls recruited in the USA was studied. No significant association was found for the PRNP polymorphism in AD compared to controls either in Probable or in Definite AD series even after stratification for APOE polymorphism. This study does not support a role of PRNP polymorphism as a susceptibility factor for AD.

The missing ApoE allele.

The human apoE gene (APOE, GenBank accession AF261279) shows a common polymorphism, with the three epsilon2, epsilon3 and epsilon4 alleles resulting from the haplotypes of two C-->T SNPs. However, whereas the three common T-T, T-C and C-C haplotypes corresponding to the epsilon2, epsilon3 and epsilon4 alleles are well known, the last C-T haplotype (GenBank accession AY077451), encoding a fourth apoE allele, has rarely been reported. We detected this fourth allele in a Caucasian patient with motor neuron disease (MND). According to the literature we refer to this allele as epsilon3r. Although several explanations may be proposed for its formation, the existence of this fourth allele is consistent with the evolutionary hypothesis generally accepted for the apoE alleles. The rarity and physiological role of epsilon3r remains to be explained, and requires further investigation.

Influence of cognitive impairment and comorbidity on disability in hospitalized elderly patients.

BACKGROUND: The effects of cognitive impairment and comorbidity on the prevalence of disability in elderly patients who are hospitalized in acute wards are not well defined. OBJECTIVES: To evaluate the role of comorbidity and cognitive impairment on the prevalence of disability in a cohort of hospitalized older patients. PATIENTS AND METHODS: This study included 179 patients aged 65 years and over admitted to the Geriatric Unit of the Casa Sollievo della Sofferenza Hospital, in Italy. Cognitive status was evaluated by means of the Mini Mental State Examination (MMSE) and Clinical Dementia Rating Scale (CDR); the functional status was evaluated according to the Activity of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) indices. Comorbidity was identified using the Cumulative Illness Rating Scale (CIRS index). RESULTS: Of the 179 patients enrolled 73 patients were diagnosed with dementia [Alzheimers' Disease (AD) = 49 patients, Vascular Dementia (VD) = 24 patients], 35 patients with Mild Cognitive Impairment (MCI) and 71 patients had no cognitive impairment. The severity of disability was significantly higher in patients with dementia (ADL = 3.1 +/- 2.1, IADL = 1.5 +/- 2.0) than patients with MCI (ADL = 5.1 +/- 1.4, IADL = 5.2 +/- 2.2) (p < 0.0001) and patients without cognitive impairment (ADL = 5.5 +/- 0.9, IADL = 6.4 +/- 1.9) (p < 0.0001). No significant differences in CIRS index were observed between patients with dementia and MCI and no cognitive impairment patients (Dementia = 2.4 +/- 1.4 vs MCI = 2.9 +/- 1.4 vs No cognitive impairment = 2.7 +/- 1.2; p = 0.1). Moreover, a significant correlation between cognitive impairment and functional status (MMSE/ADL: r = 0.45, p = 0.0001, MMSE/IADL: r = 0.54, p = 0.0001) but not between comorbidity and functional status (CIRS/ADL: r = 0.0007, CIRS/IADL: r = 0.040) was observed. Separating patients with dementia by diagnosis of AD or VD, no significant differences in MMSE (AD = 12.2 +/- 6.7 vs VD = 13.2 +/- 6.5, p = 0.6), CDR (AD = 2.2 +/- 0.8 vs VD = 2.1 +/- 0.7, p = 0.6), ADL (AD = 3.1 +/- 2.1 vs VD = 3.0 +/- 2.1, p = 0.8), IADL (AD = 1.3 +/- 1.9 vs VD = 2.0 +/- 2.2, p = 0.1) or CIRS (AD = 2.2 +/- 1.5 vs VD = 2.8 +/- 1.3, p = 0.06) scores were observed. CONCLUSIONS: Cognitive impairment and not comorbidity, was significantly associated with disability in hospitalized older patients.

Alzheimer disease risk associated with APOE4 is modified by STH gene polymorphism.

The association of the STH gene polymorphism with Alzheimer disease (AD) is debated. In the analysis of two genetically and diagnostically distinct groups of Alzheimer patients from the USA and Italy, the authors did not find an association with the STH polymorphism. However, the APOE-4-associated risk of AD greatly increased if the STH-G allele was also present. The STH-G allele appears to be a risk modifier for AD.

Sensitive detection of transitional cell carcinoma of the bladder by microsatellite analysis of cells exfoliated in urine.

Transitional cell carcinoma (TCC) is the most common bladder tumor. Urine cytology can identify most high-grade tumors but sensitivity is lower if one includes lesions of all grades. Microsatellite marker alterations have been found in many tumor types including bladder cancer and have been used to detect cancer cells in body fluids including urine. The aim of our study is to further evaluate feasibility and sensitivity of microsatellite analysis to detect bladder cancer cells in urine. We studied 55 individuals: 21 with symptoms suggestive of bladder cancer, 23 patients with previous history of TCC and 11 healthy subjects. Genomic DNA was extracted from blood lymphocytes, urine sediment, bladder washings and tumor or normal bladder mucosa. Twenty highly informative microsatellite markers were analyzed for loss of heterozigosity (LOH) and microsatellite instability (MIN) by polymerase chain reaction. Microsatellite analysis of urine identified 33 of 34 (97%) patients with either primary or tumor recurrence, whereas urine cytology identified 27 of 34 (79%) patients (p = 0.0001). Detection of microsatellite abnormalities improved the sensitivity of detecting low-grade and/or stage bladder tumor: from 75-95% for grades G1-G2 and from 75-100% for pTis-pTa tumors. Bladder washings from 25 patients were also analyzed, and in all cases results were identical to those obtained from voided urine. None of the 16 patients without evidence of TCC showed LOH and/or MIN in urine samples or bladder washings. Interestingly, in a patient with persistent bladder mucosa abnormalities, microsatellite alterations were demonstrated 8 months before the histopathologic diagnosis of tumor recurrence. These results further indicate that microsatellite marker analysis is more sensitive than conventional urine cytology in detecting bladder cancer cells in urine and represents a potential clinical tool for monitoring patients with low-grade/stage TCC.

Ext-mutation analysis in Italian sporadic and hereditary osteochondromas.

Osteochondromas represent the largest group of benign tumors of bone. Multiple osteochondromatosis or hereditary multiple exostoses (EXT) is an autosomal dominant inherited disorder characterized by the presence of multiple benign cartilage-capped exostoses. EXT is genetically heterogeneous with at least 3 chromosomal loci: EXT1 (8q24.1), EXT2 (11p11-p13), and EXT3 (19p). In <5% of EXT patients, the inactivation of both copies of EXT alleles (LOH) is associated with malignant transformation. We have analyzed the EXT1 and EXT2 genes in 9 unrelated EXT families and in a patient with a sporadic osteochondroma, all originating from Italy. Four families show an EXT1 mutation, consisting of a small deletion in 3 of them and a small insertion in the 4th. All these mutations lead to premature termination of translation and thus a truncated EXT1 protein. Three families presented EXT2 mutations consisting of nucleotide substitutions leading to alterations of the third intron splice-site, to an amino acid substitution and to a nonsense mutation. All these mutations cosegregate with the disease phenotype. The sporadic osteochondroma patient carried a novel missense mutation in exon 11 of EXT2 gene, leading to an amino acid substitution. Seven of these mutations have never been described before. EXT2 missense mutations were also confirmed by amino acids conservation between human and mouse and by analysis of a healthy control population. In conclusion, our study provide further evidence that loss of function of the EXT1 or EXT2 gene is the main cause of EXT supporting the putative tumor-suppressor function of these genes.

The Apolipoprotein E genotype in patients affected by syndromes with focal cortical atrophy.

The role of the Apolipoprotein E (APOE) alleles in syndromes associated with focal cerebral atrophy (fronto-temporal dementia, primary progressive aphasia, corticobasal degeneration) is still controversial. We studied the APOE allele distribution in 39 patients with clinically diagnosed syndromes associated with focal cerebral atrophy (FCA), in 50 patients with early-onset probable Alzheimer's disease (EOAD), and in 60 patients with late-onset probable AD (LOAD). The APOE genotype was determined from a blood sample, using polymerase chain reaction and restriction enzyme digestion. The APOE epsilon4 allele frequency was significantly higher in the EOAD (21.0%) and LOAD (33.3%) groups, but not in the FCA group (5.1%), as compared with controls. In our population, the epsilon2 allele frequency was significantly higher in patients with FCA (12.8%) than in controls (4.8%). These results show that the APOE epsilon4 allele is not a risk factor for syndromes associated with FCA. The potential role of the epsilon2 allele in these syndromes needs further investigation.