Incidence and de novo mutation rate of Marfan syndrome and risk of ectopia lentis

PURPOSE To investigate the population-based incidence and de novo mutation rate of Marfan syndrome and risk of ectopia lentis.METHODS Patients newly diagnosed with Marfan syndrome in Olmsted County, Minnesota, from January 1, 1976, through December 31, 2005, were identified through medical records review. Outcome measures were Marfan incidence, de novo mutation rate, risk of ectopia lentis.RESULTS Marfan syndrome was identified in 17 patients during the 30-year period, yielding an incidence of 0.52 per 100,000 people/year (95% CI, 0.27-0.77). Mean age at diagnosis was 24.4 years (range, 1.7 year to 51.3 years). Nine patients (53%) were female. Of the 17, 5 (29%) were new mutations, with a calculated mutation rate of 3.8 +/- 1.7 x 10-5. Four (24%) were diagnosed with ectopia lentis, including 3 at the time of their Marfan diagnosis. Of the 14 patients at risk for developing ectopia lentis after being diagnosed with Marfan syndrome, 1 (7%) developed it during a mean follow-up of 9 years (range, 0-6.4). Twelve (71%) were diagnosed with dilated ascending aorta during a mean follow-up of 13.2 years (range, 6.7 months to 28.9 years).CONCLUSIONS Incidence and de novo mutation rate of Marfan syndrome in this population-based cohort was higher than prior reports. Ectopia lentis, whose prevalence in North America has not been reported previously, occurred in approximately one-fourth of study patients and more commonly around the time of initial Marfan diagnosis. ( J AAPOS 2023;27:273.e1-4)