Fetal MR imaging of Kniest dysplasia.

We present a case of Kniest dysplasia, a rare form of the type II collagenopathies, with prenatal MRI. Sonography revealed only short limbs in the fetus. Fetal MRI findings included enlarged hyaline cartilaginous structures with abnormally high T2 signal intensity, delayed ossification of the pubic and ischial bones, and platyspondyly. By delineating the cartilaginous abnormalities, fetal MRI can contribute to the prenatal diagnosis of chondrodysplasias.