Clinical, cytogenetic, and molecular diagnosis of Angelman syndrome: Estimated prevalence rate in a Danish county

Angelman syndrome (AS) was initially considered a rather rare abnormality, but in later years, with the possibilities for cytogenetic and molecular diagnosis an increasing number of patients have been reported. The incidence is quoted to be around 1:20,000. The etiology of AS is associated with the lack of maternal allele(s) of one or more loci at 15q11-q13, and is considered an effect of parental imprinting of that region, since a similar deficiency of paternal alleles leads to Prader-Willi syndrome. 9 refs., 1 tab.