Inheritance: autosomal recessive
Chromosomal defect location: 15q13
Gene affected: IFT80 (encodes an intraflagellar protein). possibly others
Clinical features:
(1) A small, narrow chest is characteristic.
(2) variable shortening of the extremities
(3) variable post-axial polydactyly of hands and feet
(4) respiratory distress and recurrent respiratory infections starting in the neonatal period, but these tend to decrease after early childhood.
(5) antenatal polyhydramnios
(6) variable renal failure if there is survival beyond childhood
(7) variable hepatic and pancreatic abnormalities if there is survival beyond childhood
(8) variable retinal abnormalities, with night blindness, pigment in epithelial cells and/or other abnormalities
Imaging findings:
(1) bell-shaped thorax, narrow superiorly than flaring out
(2) elevated clavicles
(3) short iliac bones with the acetabula having a trident appearance
(4) hypoplastic phalanges in hands and feet with cone-shaped epiphyses
(5) variable short but wide long bones in the extremities
