The Athabaskan brainstem dysgenesis syndrome (ABDS) is a recessive genetic disorder with the following features: horizontal gaze palsy, sensorineural deafness, central hypoventilation, and developmental delay. These features significantly overlap with another congenital syndrome; the Bosley-Salih-Alorainy syndrome (BSAS). The phenotype of the latter syndrome includes horizontal gaze abnormalities, deafness, facial weakness, hypoventilation, vascular malformations of the internal carotid arteries, and cardiac outflow tract, mental retardation and autism spectrum disorder.
Importantly, many cases with BSAS suffered certain characteristic features of ABDS and vice versa, making it difficult to distinguish between these two syndromic variants especially that they result from mutations in the same gene (HOXA1). HOXA1 functions to ensure the correct placement of hindbrain segments in the proper location along the anterior-posterior axis during development.