Purpose: To elucidate demographic and nosologic characteristics of congenital ectopia lentis (ECL) in Denmark.
Methods: A register of affected persons was established based on information provided from medical records and files in a nation-wide retrospective study, the Danish ECL-study.
Results: Three hundred and ninety-six cases (197 males, 199 females) with ECL were included in the study. By January 1st, 1993, the estimated prevalence rate of ECL was 6.4/100,000. The estimated average point prevalence rate at birth 1976-85 was 0.83/10,000 live born. Only in 69% of the cases (274/396) was a nosologic classification possible, based on preexisting information about familial occurrence, systemic and ocular findings: Marfan syndrome was found in 68.2% of these (187/274), ectopia lentis et pupillae in 21.2%, simple dominant ectopia lentis in 8.0%, homocystinuria in 1.1%, sulfite oxidase deficiency and Weill-Marchesani syndrome in 0.7% each. In the remaining 31% (122/396) a nosologic diagnosis could not be established.
Conclusion: The majority of affected persons have congenital ectopia lentis as a manifestation of a systemic disease. It is therefore essential to evaluate ECL patients systemically with a general physical examination, a metabolic screening, and an echocardiography as a minimum, in order to make a nosologic diagnosis and to prevent potentially life-threatening systemic complications.