[MIM*250600] a skeletal dysplasia characterized by disproportionate dwarfism in which the trunk is long relative to the limbs at birth, but undergoes reversal of this proportion with subsequent development with severe and progressive kyphoscoliosis; there is metaphysial flare of long bones, the pelvis is halberd-shaped, and the coccyx is long, resulting in a sacral appendage; autosomal recessive inheritance.