Incidence of Sturge-Weber Syndrome and Risk of Secondary Glaucoma: A Nationwide Population-based Study Using a Rare Disease Registry.

PURPOSE: To determine Sturge-Weber syndrome (SWS) incidence and secondary glaucoma risk. DESIGN: Nationwide retrospective cohort study. METHODS: The Korean National Health Insurance (NHI) claims database from 2002 to 2019 along with the registration-program database for rare intractable diseases (ie, the rare disease registry) were accessed to identify ophthalmologist/neurologist-confirmed SWS patients. SWS incidence was estimated in a same-birth-year population (ie, a birth cohort) from 2002 to 2009. Among the SWS patients born between 2002 and 2019, the incidence of SWS-associated glaucoma was estimated. RESULTS: During the 18-year observational period, a total of 1049 patients were registered as SWS. The mean birth-cohort SWS incidence was 3.08 (95% CI 2.52-3.64) per 100 000 people per year, with an approximate female-to-male ratio of 0.97:1. Among the 217 SWS patients born between 2002 and 2019, secondary glaucoma arose in 18 (8.3%) cases, including 12 males (66.7%). Among these 18 SWS-associated glaucoma cases, 15 (83.3%) were diagnosed before 1 year of age, and the other 3 (16.7%) between age 1 and 2 years. Among the 660 SWS patients under age 40 years during the study period, SWS-associated glaucoma was identified in 79 (12.0%) cases. Neurologic manifestations such as epilepsy, hemiparesis, and mental retardation did not significantly differ between SWS patients with and those without secondary glaucoma. CONCLUSIONS: This study identified birth-cohort SWS incidence and determined secondary-glaucoma risk in a population of East Asian ethnicity. These data could help to promote better understanding of the epidemiologic features of SWS patients.