Hereditary Crystalline Degeneration of the Cornea

(Summary. A paper will be published in extenso) Clinical and genetic particulars Description of 2 families in which this condition occurs. The first family is the same as the one described by Van Went and Wibaut in 1924. The condition occurred 20 times in 5 generations. The clinical picture shows considerable variations. The association of genu valgum in 15 of the 20 affected members of the family is noteworthy. In one case genu valgum was found without cornea dystrophy. Autosomal dominant heredity was clearly indicated in this family. The genu valgum and the cornea dystrophy were presumably determined by separate genes which showed quite a high degree of coupling. The cases in which only one of the 2 conditions occurred could be explained by crossing over. The second family included two generations, in which cornea dystrophy occurred in 4 out of 5 children in the second generation. Therapy and histology Although this condition is generally considered to be clinically of no great importance, in 5 patients from these two families corneal grafts were performed on the grounds of insufficient vision. Four of these patients are described. In three the graft was penetrating and in one lamellar. The condition reappeared eventually in all the grafts, but most rapidly in the lamellar graft. The visual improvement was also greater after the penetrating than after the lamellar grafts. By means of microscopy with polarized light, fat staining and Schulz’s histochemical reaction for cholesterol, it could be proved that the crystals are composed of cholesterol. An autosomal domi626 Delleman and Winkelman nant hereditary disturbance of the cholesterol metabolism, probably enzymatic, seems to be the cause of the condition, and the question as to whether this is restricted to the cornea or is more generalized remains as yet unanswered. Discussion Vclzebo€Γ points out that the cornea is a favourite site for metabolic disturbances. In patients with angiokeratoma, in whom the lipoid metabolism is disturbed, the typical vertebra-shaped opacity in the cornea was always found, even when no clinical symptoms were present. In these patients only the skin biopsy and the corneal examination were positive. Waardenburg: My congratulations on these beautiful pedigrees. Van Went and Wibaut, with their less specialized instruments, also saw that the opacities were not restricted to the anterior layers of the cornea. In your second pedigree one must assume that the albinism of one child out of the consanguineous marriage is due to recessive heredity, but that the affected father of the