Genetic basis of Prader-Willi and Angelman syndromes: Implications for diagnostic testing.

Prader-Willi and Angelman syndromes are two genetic diseases whose clinical diagnosis is often impaired by a wide variability in some clinical findings. New insights in the genetic basis of these disorders allow the proposition of a biological approach to detect almost all Prader-Willi syndrome patients and over 80% of Angelman syndrome patients. Moreover, the results of these tests are indispensable for the evaluation of the recurrence risk. (C) 1998, Elsevier, Paris.