title: X-linked Adrenoleukodystrophy, The Tunisian Experience.
abstract: BACKGROUND
  X-linked adrenoleukodystrophy is a genetic disease affecting the degradation of very long chain fatty acids. This study aims to describe the clinical phenotype and biochemical feature of Tunisian patients; it also seeks to describe recognition of pattern analysis on the level of very long chain fatty acids in plasma for the visual discrimination of X-linked patients from a healthy group.
  
  
  METHODS
  During the last 21 years, 19 patients were diagnosed with X-linked adrenoleukodystrophy based on the clinical features combined with the area percentage of hexacosanoic acid (C26:0) as well as the ratio of C26:0 and lignoceric acid (C24:0) relative to behenic acid (C22:0) by gas chromatography. For the biochemical diagnosis of X-ALD with better accuracy, it has been desired to transform the numerical values of these biochemical markers into visually discriminating patterns.
  
  
  RESULTS
  The clinical features of 19 patients aged between 4 to 47 years were classified into cerebral form (57.8%), adrenomyeloneuropathic (26.3%), and a few patients were asymptomatic. The ratio C24:0/C22:0 ranged from 1.12 to 2.41 (normal value: 0.46 - 0.9) and C26:0/C22:0 ratio ranged from 0.03 to 0.36 (normal value: 0.003 - 0.009). The concentration of fatty acids with 22 or more carbons in body fluid did not change with age in control subjects and patients. For the visual diagnostic of patients, the Scatter plot was a reliable method for the diagnostic patterns of very long chain fatty acids of patients with X-linked adrenoleukodystrophy disorders.
  
  
  CONCLUSIONS
  The incidence of X-linked adrenoleukodystrophy disorders is under diagnosed in Tunisia. The diagnosis was confirmed by enzymatic activity study and molecular analysis but the analysis of very long chain fatty acids by gas chromatography remains a reliable tool for the diagnosis and early initiation of the treatment.
authors.forename: Fahmi
authors.initials: F
authors.lastname: Nasrallah
authors.forename: Ichraf
authors.initials: I
authors.lastname: Kraoua
authors.forename: Wiem
authors.initials: W
authors.lastname: Zidi
authors.forename: Souheil
authors.initials: S
authors.lastname: Omar
authors.forename: Haifa
authors.initials: H
authors.lastname: Sanhaji
authors.forename: Moncef
authors.initials: M
authors.lastname: Feki
authors.forename: Ilhem Turki
authors.initials: IT
authors.lastname: Ben Youssef
authors.forename: Naziha
authors.initials: N
authors.lastname: Kaabachi
mesh_terms: D000293:Adolescent; D000326:Adrenoleukodystrophy / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology*; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002849:Chromatography, Gas; D005192:Family Health; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010363:Pattern Recognition, Automated; D010641:Phenotype; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014416:Tunisia / Q000453:epidemiology
chemical_list: D005227:Fatty Acids; C017364:hexacosanoic acid; C007547:behenic acid; C010210:lignoceric acid