Epidemiology of Cornelia de Lange's syndrome.

A prevalence investigation of Cornelia de Lange's syndrome in Denmark is presented. The patients were traced by screening all institutional mentally retarded patients, patients in schools and kindergartens for imbecile patients and finally by getting information on Cornelia de Lange patients known to pediatric departments. In this way 24 patients, 10 men and 14 women, were found. This amounts to a population prevalence of 0.5/100 000. Clinical data, histories of the patients and genealogical data are presented by means of tables. The eldest patient was 49 years old, but 75% of the patients were younger than 20 years. Two of the probands were sibs. Another 2 sibs were registered as mentally retarded without specific syndromes. One case of consanguinity among parents was found. The mode of ascertainment is discussed and it is concluded that the present investigation presents a minimum prevalence figure. Four patients are presented who for various reasons were not available during the prevalence investigation proper. A prevalence figure of 0.6/100 000 is found if these 4 patients are included in the calculations. One of the last mentioned patients represented a familial case. The patient in question was a girl with a younger half-brother, the mother in common, both children being very typical cases of Cornella de Lange's syndrome.