Ls. Kirsch et al., A HISTOPATHOLOGICAL, ULTRASTRUCTURAL AND IMMUNOHISTOCHEMICAL STUDY OFCONGENITAL HEREDITARY RETINOSCHISIS, Canadian journal of ophthalmology, 31(6), 1996, pp. 301-310
Objective: To confirm our earlier histopathological and electron micro
scopic findings in congenital hereditary retinoschisis (CHRS) in two a
dditional globes and to further evaluate the nature and origin of the
intraretinal filaments by means of immunohistochemical analysis. Patie
nts: Three white men with CHRS, aged 83 years (patient I) (two globes)
, 55 years (patient 2) (two globes) and 33 years (patient 3, nephew of
patient 2) (one globe), Outcome measures: Findings on histopathologic
al study and electron microscopy (patient I) and immunohistochemical a
nalysis (all five globes). Results: Histopathological examination show
ed extensive extracellular deposition of amorphous material positive f
or periodic acid-Schiff reagent in the outer schisis layer and focally
in the macula, Ultrastructurally, the amorphous material represented
filaments measuring 8 to 12 nm in diameter within degenerated Muller c
ells, with accumulation of these filaments in adjacent extracellular s
paces. Similar, less severe changes were seen in the superonasal retin
a. Immunohistochemical studies showed focal reactivity for glial fibri
llary acidic protein (GFAP) in the retina adjacent to the schisis cavi
ty in all five globes, focal reactivity for S-100 protein in four reti
nas, rare focal staining for vimentin and neurofilaments in two retina
s each and no reactivity for type I keratin or actin. Conclusions: The
present study corroborates our previous work and provides pathologica
l evidence that the retinal disorder extends beyond the limits of the
schisis. The results of the immunohistochemical analysis are consisten
t with a glial cell origin of the filaments. We postulate that defecti
ve Muller cells produce GFAP and possibly S-100 protein, which accumul
ate within the retina and secondarily result in degeneration of these
cells and schisis formation.