Concordance for curve type in familial idiopathic scoliosis: a survey of one hundred families.
METHODS
Prospective comparative study on 100 patients with positive family history for idiopathic scoliosis.


OBJECTIVE
To evaluate the concordance rate for curve pattern and side in family members with idiopathic scoliosis.


BACKGROUND
The pathogenesis of idiopathic scoliosis has been the subject of extensive research. It is termed multifactorial with a genetic component. Similar curve shape has been reported in twins with idiopathic scoliosis.


METHODS
We included prospectively 100 patients with idiopathic scoliosis when a relative of them was also affected with idiopathic scoliosis, and spine radiographs were available for both. Concordance for curve pattern by Lenke classification and side between family members was analyzed.


RESULTS
Familial concordance rate for curve pattern and side was 66% (95% confidence interval, 57-75), whereas the expected random concordance rate was 26% (95% confidence interval, 17-34). The affected relative was in 27 cases a sibling, in 32 cases a parent, in 1 case an uncle, in 2 cases a cousin, in 2 cases a half sister, in 2 cases a grandmother. Concordance rate was 65% (27/42) in siblings' pairs and 67% (32/48) in parents/child's pairs.


CONCLUSIONS
We report a high concordance rate for curve pattern and side between relatives with idiopathic scoliosis. Curve shape is likely to be genetically determined in familial scoliosis. It seems important that curve type is documented and considered in future genetic studies.
Sales de Gauzy
Jérôme
J
Department of Pediatric Orthopaedic Surgery, Hôpital des Enfants, Toulouse, France.
Ballouhey
Quentin
Q
Arnaud
Catherine
C
Grandjean
Hélène
H
Accadbled
Franck
F
D000293:Adolescent; D002648:Child; D005190:Family; D005260:Female; D006306:Health Surveys; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D011446:Prospective Studies; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging* / Q000235:genetics*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging*; D055815:Young Adult