title: Apolipoprotein E genotype does not associate with disease severity measured by Multiple Sclerosis Severity Score.
abstract: OBJECTIVE
  During the last years, the association between apolipoprotein E (APOE) polymorphism and disease severity in multiple sclerosis (MS) has been studied with conflicting results. As a result of a considerable individual variation in the clinical course of MS, there is no consensus method for measuring progression using single assessments of disability. Recently, Multiple Sclerosis Severity Score (MSSS) method has been proposed for comparing disease progression using single data. We evaluate in our population if there is any correlation between APOE genotype and severity according to MSSS.
  
  
  METHODS
  We studied 82 patients followed up in our Neurology Unit throughout the year 2005, diagnosed with MS, and with disease duration of at least 2 years. We collected data concerning demographic and clinical variables including age of onset, disease duration, Expanded Disability Status Scale (EDSS) score and the total number of relapses. When reached, we determined the latency to EDSS scores of 4.0 and 6.0. We calculated progression index (PI) and relapse rate (RR). We ascertained MSSS for our patients in the global MSSS table.
  
  
  RESULTS
  We found four patients heterozygous for the E2 allele and 16 for the E4 allele. No patient was homozygous for E2 or E4. RR (P = 0.017 with 95% CI: 0.005-0.57) and PI (P = 0.016 with 95% CI: 0.004-0.38) were significantly lower in E4 carriers. MSSS scores were not associated with carriership of E2 or E4.
  
  
  CONCLUSIONS
  Our results show no effect of the APOE genotype on the severity of MS measured by MSSS, as a recently published meta-analysis has noticed. So, our data do not support a role for APOE in MS severity, in spite of the seeming influence shown using other measures such as PI. MSSS is probably the best method to measure severity with a single measure of disability and should be used more frequently when performing genetic research.
authors: Neurology Unit, Hospital Río Carrión, Palencia, Spain. aguerrero@hrcr.sacyl.es
authors: A L
authors: AL
authors: Guerrero
authors: E
authors: E
authors: Laherrán
authors: F
authors: F
authors: Gutiérrez
authors: J
authors: J
authors: Martín-Polo
authors: F
authors: F
authors: Iglesias
authors: C
authors: C
authors: Alcázar
authors: J
authors: J
authors: Peralta
authors: P
authors: P
authors: Rostami
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D053329:Apolipoprotein E2 / Q000235:genetics; D053327:Apolipoprotein E4 / Q000235:genetics; D001057:Apolipoproteins E / Q000235:genetics*; D004252:DNA Mutational Analysis; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000235:genetics* / Q000378:metabolism* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012008:Recurrence; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D053329:Apolipoprotein E2; D053327:Apolipoprotein E4; D001057:Apolipoproteins E; D005819:Genetic Markers