title: Radiologic phenotypes in lumbar MR imaging for a gene defect in the COL9A3 gene of type IX collagen.
abstract: OBJECTIVE
  To evaluate whether the COL9A3 tryptophan allele (Trp3 allele) is associated with a specific radiologic phenotype among patients with sciatica.
  
  
  METHODS
  One hundred fifty-three patients with sciatica were evaluated for the presence of Trp3 allele, Scheuermann disease, intervertebral disk degeneration, Schmorl nodules, dorsal anular tears, hyperintense lesions, and endplate degeneration on sagittal T2-weighted lumbar magnetic resonance images. The Trp3 genotype was determined by means of sequencing the COL9A3 gene. Radiologic phenotypes were evaluated while blinded to the genotype. Scheuermann disease was diagnosed if either endplate irregularities or Schmorl nodules and two of the other three criteria (disk space narrowing, disk dehydration, and wedging of anterior vertebral body margins) were present at three or more adjacent disk levels from T10-11 to L3-4. Disk degeneration was evaluated separately for each disk (T11-12 to L5-S1) and for all disks combined. Frequencies of radiologic phenotypes between individuals with or without Trp3 allele were compared.
  
  
  RESULTS
  Thirty-four patients had at least one Trp3 allele. When compared with the matched control subjects, they had an increased likelihood of Scheuermann disease (P =.035) and an increased number of degenerated disks from T11 to S1 (P =.021). Comparisons at individual disks showed a statistically significant increase in disk degeneration at T11-12 (analysis of all grades of degeneration [graded], P =.018; analysis of any degeneration vs none [dichotomous], P =.039) and L4-5 (graded, P =.011; dichotomous, P =.016). Prevalences of anular tears, endplate degeneration, Schmorl nodules, and hyperintense lesions were comparable.
  
  
  CONCLUSIONS
  The results of this study indicate that the presence of Trp3 allele is associated with Scheuermann disease and intervertebral disk degeneration. No associations were found for other radiologic phenotypes.
authors.affiliation: Department of Physical Medicine and Rehabilitation, University Hospital of Oulu, PL 25, FIN-90029 Oulu, Finland. jaro.karppinen@ttl.fi
authors.forename: Jaro
authors.initials: J
authors.lastname: Karppinen
authors.forename: Eija
authors.initials: E
authors.lastname: Pääkkö
authors.forename: Petteri
authors.initials: P
authors.lastname: Paassilta
authors.forename: Jaana
authors.initials: J
authors.lastname: Lohiniva
authors.forename: Mauno
authors.initials: M
authors.lastname: Kurunlahti
authors.forename: Osmo
authors.initials: O
authors.lastname: Tervonen
authors.forename: Pentti
authors.initials: P
authors.lastname: Nieminen
authors.forename: Harald H H
authors.initials: HH
authors.lastname: Göring
authors.forename: Antti
authors.initials: A
authors.lastname: Malmivaara
authors.forename: Heikki
authors.initials: H
authors.lastname: Vanharanta
authors.forename: Leena
authors.initials: L
authors.lastname: Ala-Kokko
mesh_terms: D024081:Collagen Type IX / Q000235:genetics*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010641:Phenotype
chemical_list: C120768:COL9A3 protein, human; D024081:Collagen Type IX