Therefore, the hydrocephalus may be due to abnormal signalling downstream of cilia flow, or conversely may be due to mis-patterning of the brain.59 60 In this latter regard, DLG5 at the cilium appears to modulate Shh signalling via interactions with Smo.19 Shh signalling in turn orchestrates embryonic patterning including that of the digits of the limb and the kidney.61–63 Indeed, Shh signalling appeared disrupted based on the decreased expression of foxf1 and the expansion of Pax6 expression observed on dlg5 depletion. The gene discussed is SMO; the disease is Hydrocephalus.