Type I collagen alpha1 Sp1 polymorphism and the risk of cruciate ligament ruptures or shoulder dislocations.
BACKGROUND
Cruciate ligament ruptures and shoulder dislocations are often caused by trauma, but predisposing intrinsic factors might also influence the risk. These injuries are more common in those with a previously injured sibling, an observation that might indicate a genetic predisposition. It is well known that polymorphisms in the collagen I gene are associated not only with osteoporosis and osteoporotic fracture risk, but also with osteoarthritis.


OBJECTIVE
Because collagen I is abundant in ligaments and tendons, the authors hypothesized that collagen I alpha1 Sp1 polymorphism also was related to the occurrence of cruciate ligament ruptures and shoulder dislocations.


METHODS
Case-control study; Level of evidence, 3.


METHODS
A total of 358 patients and 325 randomly selected population-based female controls were included in the study. Of the cases, 233 had a cruciate ligament rupture and 126 had had a shoulder dislocation. Age-adjusted odds ratios (ORs) with 95% confidence intervals (CIs) estimated by unconditional logistic regression were used as measures of association.


RESULTS
Compared with the homozygous SS category, the heterozygous participants displayed a similar risk (OR, 1.06; 95% CI, 0.76-1.49), whereas the ss genotype was underrepresented in the injured population compared with the controls (OR, 0.15; 95% CI, 0.03-0.68). This latter estimate was similar for both cruciate ligament ruptures and shoulder dislocations, and was furthermore not modified by general joint laxity.


CONCLUSIONS
The authors found a substantially decreased risk of these injuries associated with collagen type I alpha1 Sp1 polymorphism. The study might encourage other investigators to consider further research in the area of genes and soft tissue injuries.
Khoschnau
Shwan
S
Department of Surgical Sciences, Section of Orthopedics, University Hospital, Uppsala, Sweden. m_shwan@hotmail.com
Melhus
Håkan
H
Jacobson
Annica
A
Rahme
Hans
H
Bengtsson
Henrik
H
Ribom
Eva
E
Grundberg
Elin
E
Mallmin
Hans
H
Michaëlsson
Karl
K
D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D016022:Case-Control Studies; D024042:Collagen Type I / Q000235:genetics*; D000090602:Collagen Type I, alpha 1 Chain; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D016119:Posterior Cruciate Ligament / Q000293:injuries*; D012307:Risk Factors; D012783:Shoulder Dislocation / Q000235:genetics*; D017695:Soft Tissue Injuries / Q000235:genetics*; D055815:Young Adult
D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain