Phenotypic criteria for early-onset glaucoma in patients with anterior segment mesenchymal dysgenesis

Anterior segment mesenchymal dysgenesis comprises a broad group of phenotypically and genetically heterogeneous diseases that are frequently associated with the development of glaucoma in early childhood. One of the most common conditions within this group is Frank – Kamenetsky syndrome, which has an X-linked mode of inheritance and is characterized by distinctive abnormalities of the anterior segment of the eye, including features of goniodysgenesis. Identification of biological markers of the onset and manifestation of hydrodynamic disturbances remains an important challenge in ophthalmology. PURPOSE. To identify phenotypic criteria for early-onset glaucoma in Frank – Kamenetsky syndrome. METHODS. A comparative retrospective analysis of phenotypic features of Frank – Kamenetsky syndrome was performed in patients from two groups stratified according to the timing of glaucoma manifestation. Group 1 included 22 patients in whom elevated intraocular pressure (IOP) and the first signs of glaucoma were documented at the age of 5–10 years. Group 2 comprised 14 patients in whom persistent IOP elevation and signs of glaucomatous optic neuropathy were diagnosed after the age of 20 years. RESULTS. Phenotypic criteria associated with early-onset glaucoma in patients with Frank – Kamenetsky syndrome included congenital non-progressive megalocornea (corneal diameter >12 mm), grade II–III goniodysgenesis, and iris stromal thickness <50 μm, indicating a combination of defects in the embryonic development of all mesenchymal tissue derivatives. CONCLUSION. The abnormal phenotype of Frank – Kamenetsky syndrome can be readily distinguished from normal anatomy by the presence of specific and characteristic alterations of the iris and the anterior segment as a whole. At the same time, this disease demonstrates marked variability in the severity and range of clinical manifestations, as well as in the time of glaucoma onset. Differences in phenotypic expression of the abnormal genotype may lead to difficulties in interpreting the diagnosis and delayed identification of hydrodynamic disturbances and glaucomatous optic neuropathy.