Abnormal retinal projections in cats with the Chediak-Higashi syndrome

The Chediak-Higashi syndrome (CHS) occurs in mammals, including humans and cats. The CHS is characterized by decreased oculocutaneous pigmentation, enlarged cytoplasmic granules, increased susceptibility to infections, and a hemorrhagic tendency. Ocular anomalies include pale irides and albinotic or subalbinotic fundi. Cats with CHS also have photophobia and prolonged postrotatory nystagmus. Since hypopigmentation of the pigment epithelium is correlated with misrouting of retinal ganglion cells in mammals, visual projections of CHS cats were examined by autoradiographic techniques to determine whether they exhibit abnormal retinogeniculate projections. In CHS cats, misrouted optic projections fragment layer A1 of the dorsal lateral geniculate nucleus into several islands, similar to the disruption of this lamina reported in the Siamese cat.