RESUMEN
On the Ucka hill-side, in the Veli Brgud village, Opatija County, Istrian peninsula, Republic of Croatia, there is a great number of patients with glaucoma simplex congenitum (open angle glaucoma) among a total of 550 Croatian inhabitants. Of these, 536 (97.5%) were ophthalmologically examined and glaucoma simplex congenitum was diagnosed in 74 persons, some of them already blind. The proportion of the affected was 13.8%. The cases were largely from the Afric family (nicknamed "Sor"). The pedigree of the Afric-"Sor" family has 1215 members through nine generations, descendants of Matheus Afric (1762) and Marija Bratovic (1765). In the total of 536 examined, 291 (54%) belong to this pedigree, whereas 67 (90%) out of 74 affected persons were of the same pedigree. The rest of 7 (9.46%) affected patients did not descend from this pedigree, however, three of them (4.05%) were also from the Afric-"Sor" family, but we could not find a connection with that pedigree due to inadeguate marital data before 1760. In the Veli Brgud village, there also were 4 (5.41%) patients of non-Afric families with no other affected members. From the total of 330 marriages, 73 (22%) were consanguineous. According to our results, the mode of inheritance of glaucoma simplex in the Afric-"Sor" pedigree was of a dominant pattern.