High rate of primary congenital glaucoma found in Slovakian Roma population

The prevalence, related to a genetic mutation, in this population is higher and disease severity is greater.

BERLIN — A high rate of primary congenital glaucoma, more aggressive and refractory to treatment than average, affects the Roma population of the Slovak Republic, according to a study.

“The mean incidence is one per 700, compared to one per 15,000 in the rest of the population,” Anton Gerinec, MD, said at the World Ophthalmology Congress here.

DNA analysis showed that the high rate of primary congenital glaucoma (PCG) is related to CYP1B1 gene mutation, which probably originated from a single ancestral mutation event. The same gene mutation was not found in the rest of the glaucoma population.

“Not only the prevalence of PCG is higher in the Roma population, also the severity of the disease is greater. It seems that CYP1B1-related PCG has specific characteristics, with a different onset, course and prognosis compared to PCG in the rest of the population,” Dr. Gerinec said.

Study results

In a study conducted at the University of Bratislava, two groups of patients with PCG, Roma and non-Roma, were compared. A total of 220 eyes of 110 children were in the first group, and 177 eyes of 109 children were in the second group. Significant differences were found for all parameters.

“In almost the total number of cases (92%), PCG was present at birth in the Roma group. A later onset, up to the age of 3, was reported in 79% of the other group,” Dr. Gerinec said.

Congenital glaucoma in a Roma infant.

No treatment can improve the disease at this stage. Images: Gerinec A

The first sign of the disease in all Roma children was an enlarged, cloudy cornea, indicating that the disease had rapidly evolved to an advanced, irreversible stage. In the non-Roma group, 35% of the eyes presented first with pseudoinflammatory symptoms. Corneal diameter was larger in the Roma population, 13.3 mm compared with 12.1 mm in the non-Roma group, and axial length was longer.

In all Roma children, the disease was bilateral, while in the non-Roma group, 28.5% of the cases were unilateral.

An IOP of 35 mm Hg or higher was found in 70% of Roma patients, compared with 35% of patients in the non-Roma group. Optic disc excavation was present in a high number of eyes and low vision in 77% of the Roma children, compared with 19% of the non-Roma group, Dr. Gerinec said.

Histological samples obtained during surgery showed that trabecular dysgenesis was present in 93% of the Roma children’s eyes. Due to immature development of the trabecular meshwork, the Schlemm’s canal had not developed. The same anatomical features were found in only 6.2% of the eyes in the non-Roma group.

Severe complications of primary congenital glaucoma, such as corneal leukoma, lens dislocation, optic nerve atrophy and retinal detachment, occurred with significant frequency in the Roma population, accounting for 91% of the cases. In the non-Roma group, only 3.6% of the eyes presented severe complications while most of the sequelae (43%) were refractive and functional, such as myopia, strabismus and amblyopia.

Treatment methods

“To treat these patients, we used standard surgical methods. Goniotomy and trabeculotomy were used successfully in quite a number of cases in the second group but had poor efficacy in the Roma children. Trabeculectomy was really the only feasible attempt to treat these eyes, but in as many as 81% of the cases, second surgery — trabeculectomy with mitomycin C, implantation of a drainage implant, photocoagulation or iridocycloretraction — was needed. Much fewer eyes, 16%, were reoperated in the other group,” Dr. Gerinec said.

One year after surgery, IOP stabilization was achieved in 8.6% of eyes in the Roma group and in 91% of eyes in the non-Roma group.

“Only very few eyes, 9%, were able to recover normal functional vision in the Roma group. In spite of all the attempts to treat these children, 51% had low vision and 40% were blind,” Dr. Gerinec said.

Results were better in the non-Roma group of eyes, where normal vision was recovered in 57% of the cases. Of those, 39.4% had low vision and 3.6% were blind.

A screening program has been set up in the Slovak Republic in an attempt to lower the rate of primary congenital glaucoma in the Roma population.

“The incidence is currently increasing, but we have had our first success with several healthy infants born after DNA prenatal diagnosis,” Dr. Gerinec said. – by Michela Cimberle

• Anton Gerinec, MD, can be reached at Pediatric Ophthalmology Department, Comenius University, Limbova 1, 83340 Bratislava, Slovak Republic; +421-2-54776103; fax: +421-2-59371345; e-mail: gerinec@dfnsp.sk.