This is a primigravida, 25 years old, with no remarkable history and is at 19 weeks of gestational age.

4 chamber view of the heart:

Thorax and head:

Spine:

Femur and leg:

Humerus and arm:

The findings were: severe micromelia, normal mineralization of the skull and spine, bell-shaped thorax and no fractures. A diagnosis of thanatophoric dysplasia or achondrogenesis was considered. These are the postnatal photographs and radiographs.

The final diagnosis was Achondrogenesis.

Comment by Philippe Jeanty:

This case is interesting because one of the major criteria I use to recognize Achondrogenesis is the hypomineralization of the bones. Unfortunately there is no easy way to characterize hypomineralization (yes, lack of shadowing, more normal visualization behind bones and in particular behind the proximal parietal bones, visualization of both cortical of a long bones etc.. ). Many of these criteria are pretty subjective. So this case is a good reminder that achondrogenesis can present with normal echogenicity of the bone and thus be difficult to distinguish from thanatophoric dysplasia (which was my initial and many reader"s initial diagnosis)