A short-rib dysplasia with characteristics of narrow thorax, short limbs and radiological skeletal abnormalities including "trident" aspect of the acetabula and metaphyseal changes. In rare cases, postaxial polydactyly may also be present. The narrow thorax may cause neonatal respiratory failure, and may be associated with persistent respiratory manifestations. The growth rate is variable but may be almost normal. Intellectual development is normal. The molecular basis of the syndrome has been partially elucidated indicating involvement of the IFT80 (3q25.33), DYNC2H1 (11q22.3), WDR19 (4p14) and TTC21B (2q24.3) genes, each encoding an intraflagellar transport protein. The syndrome is transmitted as an autosomal recessive trait.