Hydrocephalus-inducing protein (Hydin) is required for ciliary motility []. Hydin mutations have been shown to associate with primary ciliary dyskinesia in humans [].
The ASH (ASPM-SPD-2-Hydin) domain or N-terminal domain of abnormal spindle-like microcephaly-associated protein (ASPM) is found in proteins associated with cilia, flagella, the centrosome and the Golgi complex [, ]. The domain is also found in Hydin and OCRL whose deficiencies are associated with hydrocephalus and Lowe oculocerebrorenal syndrome (OCRL), respectively. The presence of ASH in centrosomal and ciliary proteins indicates that ASPM may possess roles not only in mitotic spindle regulation, but also in ciliary and flagellar function [].