Nasal nitric oxide in patients with inherited retinal dystrophies.

Background: Ciliopathies refer to a wide variety of diseases in which mutations in the genes encoding proteins involved in ciliogenesis or protein transport to the primary cilia play pathogenetic roles, and in such diseases, retinal involvement may be present. Nitric oxide (NO) plays an important role in airway physiology, including regulation of ciliary motility and host defense. In primary ciliary dyskinesia, a syndromic ciliopathy, nasal NO (nNO) levels were reported to be extremely low compared with controls, possibly reflecting molecular defects leading to structural and functional ciliary abnormalities. We investigated whether decreased nitric levels were also present in patients with retinal inherited dystrophies.
Methods: Nasal NO was measured in a group of patients with syndromic and nonsyndromic inherited retinal dystrophies.
Results: Patients with inherited retinal dystrophies, both syndromic and nonsyndromic, had mean nNO levels that were lower than healthy controls. Seven patients had particularly low levels of nNO: 3 patients with retinitis pigmentosa and 4 individual patients with Mainzer-Saldino syndrome, Bardet-Biedl syndrome, Usher syndrome, and cone-rod disease.
Conclusions: These findings provide evidence that there is an underlying abnormal ciliary function involving the nasal epithelium in some patients with inherited retinal dystrophies.