Background
The morphological abnormality of the acetabulum in patients with primary protrusio acetabuli is almost the exact opposite as in those with developmental dysplasia of the hip. In primary protrusio acetabuli, the acetabulum is excessively deep, while in developmental dysplasia of the hip, the acetabulum is excessively shallow. A genetic etiology has been proposed in developmental dysplasia of the hip, while the etiology of primary protrusio acetabuli is widely debated. Primary protrusio acetabuli may represent a hitherto unidentified metabolic defect, and a possible candidate for such genetic influence is the R2726W variant of the fibrillin 1 (FBN1) gene, which segregates with isolated skeletal features of individuals with Marfan syndrome.
Material and Method
We identified 26 patients with primary protrusio acetabuli and 45 patients with developmental dysplasia of the hip through clinical and radiographic examinations. We included 95 normal controls in the study. DNA from peripheral blood was used in genotyping for the FBN1 R2726W mutation using pyrosequencing.
Results
No mutant alleles were identified in any patients or controls.
Conclusions
The R2726W mutation is not responsible for skeletal malformation of primary protrusio acetabuli in our population, although there may be unidentified genetic variants in either FBN1 or other genes that control acetabular morphology.

Keywords: Microfilament Proteins - genetics, Hip Dislocation, Congenital - genetics, DNA Primers, Base Sequence, Acetabulum - abnormalities, Mutation, Polymerase Chain Reaction