Apolipoprotein E genotypes associated with Alzheimer disease and concomitant stroke

BACKGROUND

The ɛ4 allele of the apolipoprotein E (APOE) gene is a well-characterized genetic risk factor for Alzheimer disease (AD). The association between stroke and a higher risk for AD has also been reported. Our study sought to determine the relationship between the APOE gene and AD and the comorbid risk of stroke.

METHODS

The subjects of this study consisted of 48 patients with AD and 48 members of a control group. All subjects were genotyped for APOE.

RESULTS

The results clearly show a significant increased risk of AD in carriers of the APOE ε3/ε4 genotype (P = .003, odds ratio [OR] = 4.1) or ε4 allele (P = .001, OR = 4.2). The risk for stroke in AD patients was also increased for carriers of the APOE ε3/ε4 genotype (P = .02, OR = 9.0) and for carriers of the APOE ε4 allele (P = .004, OR = 5.5).

CONCLUSIONS

The present study is the first to establish a relationship between APOE ε4 and concomitant AD and stroke in the Tunisian population.

Association of methylenetetrahydrofolate reductase polymorphisms with susceptibility to Alzheimer's disease

BACKGROUND

Genetic risk factors play an important role in the pathogenesis of Alzheimer's disease (AD). In this case-control study, we examined the C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and their correlation with this pathology.

OBJECTIVE

To verify the association between MTHFR C677T and A1298C polymorphisms and Alzheimer's disease.

METHOD

This work was conducted as a case-control study. Cases consisted of thirty-eight patients and 100 individuals without dementia constituted the control group. Genotyping of MTHFR polymorphisms was performed on patients and controls.

RESULT

Genetic analyses did not indicate a significant association between the MTHFR C677T mutation and AD (C/T: 63.15% versus 39%, p=0.087). However, the genotype prevalence of the missense variant MTHFR A1298C was significantly different between patients and controls (A/C: 55% versus 7%, p<10(-3)). Our data suggest an association between the MTHFR A1298C mutation and AD; however, the MTHFR C677T mutation did not contribute to susceptibility for AD.

CONCLUSION

The MTHFR A1298C polymorphism is a possible risk factor for Alzheimer's disease.

Association of methylenetetrahydrofolate reductase A1298C polymorphism but not of C677T with multiple sclerosis in Tunisian patients

BACKGROUND AND OBJECTIVE

Multiple sclerosis (MS) is a chronic neurological disease characterized by central nervous system (CNS) inflammation and demyelination of nerve axons. The aim of this study was to investigate a possible association between the methylenetetrahydrofolate reductase (MTHFR) gene and multiple sclerosis in Tunisian patients.

PATIENTS AND METHODS

The genotyping of two missense variants of the methylenetetrahydrofolate reductase (MTHFR) gene, C677T and A1298C was performed in 80 multiple sclerosis patients and 200 healthy controls.

RESULTS

No significant differences were found in the frequency of the MTHFR C677T polymorphism between MS patients and healthy controls. However, the genotype prevalence of the missense variant MTHFR A1298C was significantly different between patients and controls (A/C: 55% versus 7%, p<10(-3); C/C: 13.75% versus 0%, p<10(-3), respectively).

CONCLUSION

Although our preliminary findings suggest no association between the MTHFR C677T variants and MS, there is evidence to suggest a significant association between the MTHFR A1298C polymorphisms and MS.

Thrombophilic polymorphisms - factor V Leiden G1691A, prothrombin G20210A and MTHFR C677T - in Tunisian patients with cerebral venous thrombosis

Cerebral venous thrombosis (CVT) has been associated with thrombophilic defects. We performed a study to evaluate the role of three single nucleotide polymorphisms (SNP), factor V Leiden G1691A (FVL), prothrombin gene mutation G20210A (FII-G20210A) and methylenotetrahydrofolate reductase variant C677T (MTHFR-C677T), as risk factors for CVT in Tunisian patients. A single center case-control study (26 patients with CVT and 197 controls) was performed. Genomic DNA was tested for the three SNP. The principle finding was the association between FVL and CVT (p<0.001, Odds ratio=6.1, 95% confidence interval=2.3-16.5). However, neither the FII-G20210 (p=0.536) nor the homozygous MTHFR-C677T genotype (p=0.325) variant contributed to the risk of CVT in these Tunisian patients.

Cerebral venous thrombosis associated with homozygous factor V Leiden mutation in a 15-year-old girl of Tunisian origin

Cerebral venous thrombosis (CVT) is a rare disease. It has numerous and complex etiologies. Inherited or acquired prothrombotic states play a key role in the development of this disease, such as factor V G1691A mutation (FV Leiden). A 15-year-old girl presented to the Department of Neurology with a complaint of severe headache with visual blurring. The diagnosis of CVT was not initially suspected because of the patient's condition on presentation. An MRI showed thrombosis in the superior sagittal sinus, confirming venous stroke. Anticardiolipin and antiphospholipid antibodies were assessed. In addition, inherited prothrombotic defects, such as protein C, protein S, and antithrombin deficiencies, and genetic mutations for FV Leiden, prothrombin gene G20210A (FII G20210A), and methyltetrahydrofolate reductase C677T (MTHFR C677T) were studied. All results were unremarkable except for the unique homozygous FV Leiden mutation, which likely contributed to this prothrombotic situation. This study highlights the fact that FV Leiden may play a significant role in the onset of CVT in young patients.

Hyperhomocysteinemia, C677T MTHFR polymorphism and ischemic stroke in Tunisian patients

BACKGROUND

Hyperhomocysteinaemia has been identified as a strong risk factor for ischemic stroke (IS). A point mutation in methylene tetrahydrofolate reductase (MTHFR C677T) has been associated with increased plasma homocysteine (Hcy) levels.

AIM

This preliminary study aimed to investigate whether hyperhomocysteinaemia and/or MTHFR C677T mutation are associated with ischemic stroke.

METHODS

A case-control study including 50 consecutive patients with confirmed IS and 97 controls was performed. Fasting plasma homocysteine levels, MTHFR C677T genotypes were assessed. Other factors such as hypertension, obesity, dyslipidemia, diabetes mellitus, recurrent stroke tobacco and alcohol were investigated.

RESULTS

Mean plasma homocysteine levels were significantly higher in IS patients than in controls (15.83+/-10.60) μmol/L vs 13.78+/-6.29 μmol/L, p=0.04), while no association of MTHFR C677T variant was observed even with homocysteine. The risk to develop ischemic stroke in hyperhomocysteinemic subjects was 2.4 times more than in subjects with normal Hcy levels (OR= 2.4; 95% CI: 1.13-5.06; p<0.05).

CONCLUSION

Our findings suggest that high levels of homocysteine but not MTHFR C677T polymorphism represent risk factors for arterial ischemic stroke in Tunisian subjects.

[Brain tuberculomas: six cases]

INTRODUCTION

Despite the resurgence of tuberculosis, partly due to HIV infection, central nervous system involvement remains rare, accounting for only 2 to 5% of all tuberculosis forms. PATIENTS ET METHOD: We report six cases of brain tuberculomas occurring in patients free of HIV infection and hospitalized between 2001 and 2006 in the internal medicine department of a Tunisian military hospital (Tunis).

RESULTS

Four patients had an underlying defect. Headache, fever, consciousness disorders, deficit disorder or cerebellar syndrome are the main symptoms. Tuberculomas were multiple and disseminated in four cases and localized in the brain stem in two cases. Positive diagnosis could be established in two cases on the basis of the pathology results of a brain biopsy or detection of Mycobacterium tuberculosis in the cerebrospinal fluid; the diagnosis was presumptive in the other cases. Five patients recovered under antituberculosis treatment maintained on average 13 months (11 to 16 months). Steroid treatment was associated in five patients and tapered off for four to six weeks. One 78-year-old diabetic patient died in a context of cachexia with multiple organ failure.

[Cerebral venous thrombosis during pregnancy: about 7 cases]

BACKGROUND

cerebral venous thrombophlebitis (CVT) is a rare but serious pathology. The pregnancy and especially the postpartum constitute supporting circumstances occured of the CVT.

AIM

the aim of our study is to remember the symptomatology of CVT, the importance of the IRM and the angio IRM in the diagnosis of CVT, and its treatment.

OBSERVATIONS

We present a retrospective study relating to 7 cases of CVT during gravidopuerperality over 7 years (1996 to 2002). The average age of our patients is 32.1 years. The CVT occured during the first trimester of the pregnancy in one case and in the postpartum in 6 cases. The symptomatology was dominated by cephalgia and the signs of intracranian hypertension. Convulsions occured in 3 cases. The diagnosis of CVT was confirmed by IRM coupled with the Angio-IRM in all cases. The treatment by heparinotherapy was instaured immediately and relayed by the Anti-Vit K as the evolution was favorable in all cases.

CONCLUSION

cerebral venous thrombophebitis (CVT) is a serious pathology (especially in pregnancy and post partum). The diagnosis is performed by the magnetic resonance imaging (IRM) and the early introduction of the heparinotherapy.

Linkage to chromosome 13q11-12 of an autosomal recessive cerebellar ataxia in a Tunisian family

OBJECTIVE

To report the clinical findings and the genetic linkage mapping of an autosomal recessive cerebellar ataxia associated to peripheral neuropathy, showing an early onset cerebellar ataxia with retained tendon reflexes (EOCA) phenotype.

BACKGROUND

EOCA is a clinical syndrome delimited by Harding distinguished from Friedreich's ataxia (FA) mainly by the preservation of tendon reflexes. Molecular genetic study of patients with EOCA has demonstrated genetic heterogeneity. A form of autosomal recessive spastic ataxia has been described in Charlevoix Saguenay area in Quebec (ARSACS); the gene responsible has been mapped to chromosome 13q.

METHODS

Genetic linkage analysis was performed on 18 members of a large family including 8 of 9 members with EOCA. After exclusion of FA and ataxia with vitamin E deficiency loci as well as loci of autosomal dominant cerebellar ataxias, we performed a linkage analysis to markers of 13q11-12 region.

RESULTS

The 9 affected members of this family showed stereotyped clinical features with cerebellar ataxia, pyramidal syndrome, and a variable degree of axonal peripheral neuropathy. Linkage was detected between the disease locus and the microsatellite marker D13S232. Surrounding markers to D13S232 confirmed the linkage and showed the homozygosity of the affected members.

CONCLUSION

The family reported here showed the same locus as autosomal recessive spastic ataxia Charlevoix Saguenay disease.

Brain stem MRI signal abnormalities in CADASIL

BACKGROUND

We recently showed that the severity of MRI signal abnormalities increases with age in CADASIL, an arteriopathy due to mutations of notch 3 gene on chromosome 19. Previous results also suggest that the various hemispheric subcortical areas have a different vulnerability to ischemia in this disease. The distribution of the lesions at the brain stem level has not yet been reported.

CASE DESCRIPTIONS

We reviewed the MRIs of 68 affected patients having signal abnormalities in the hemispheric white matter to assess the distribution and clinical consequences of brain stem signal abnormalities in CADASIL. We found hypersignals on T2-weighted images in the brain stem in 45% of the subjects. The pons was more frequently involved (100%) than the mesencephalon (69%) and the medulla (35%). Hyposignals on T1-weighted images, at the brain stem level, were observed only in two thirds of these subjects. The lack of signal abnormalities reaching the brain stem surface and the absence of cerebellar lesions were noteworthy.

CONCLUSIONS

Brain stem signal abnormalities observed in CADASIL are found in regions irrigated only by perforating arteries. These results support parallel observations made for CADASIL-associated signal abnormalities in the cerebral hemispheres and emphasize the importance of the angioarchitecture of the cerebral vasculature to explain why a condition characterized by a systemic vessel wall pathology is manifested only as a brain disease.