Table 1 Molecular defects and recurrence risks in PWS.
From: Practice guidelines for the molecular analysis of Prader-Willi and Angelman syndromes
Genetic defect | Proportion of cases | Recurrence risk |
|---|---|---|
De novo deletion of 15q11-q13 on the paternal chromosome | 75-80% | <1% |
Maternal uniparental disomy (UPD) of chromosome 15 | 20-25% | <1% |
Imprinting defects (with an imprinting centre deletion excluded) | ≈1% | <1% |
Imprinting centre deletion | ≈ 10-15% of patients with an imprinting defect | Up to 50% (if present in father) |