Taking into consideration all these findings, the identification of PSIP1 as a HHL causative gene raises an intriguing question as to how mutations in a transcriptional co-activator expressed in many different cells types of the inner ear, in the retina and throughout the central nervous system can lead to a hearing-loss specific phenotype and variable visual phenotype not directly linked to retinal cells. The gene discussed is PSIP1; the disease is hearing loss disorder.