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Prader-Willi syndrome in South African patients--clinical and molecular diagnosis
A L Christianson1, D L Viljoen, W S Winship
1Department of Human Genetics and Developmental Biology, University of Pretoria.
Study Objective:
To assess clinically South African patients with the putative diagnosis of Prader-Willi syndrome (PWS) and confirm this diagnosis by DNA/molecular analysis.
Design:
Prospective, nationally based, combined clinical and laboratory study.
Main Results:
Thirty-seven patients with a putative diagnosis of PWS were examined by clinical geneticists. Only 13 (35.1%) of these patients had the diagnosis of PWS confirmed by molecular analysis, and all 13 PWS patients had positive scores using the PWS consensus diagnostic criteria of Holm et al. The clinical features of the remaining 24 (64.9%) non-PWS patients were analysed and 23 did not have the neonatal, infantile and childhood features necessary to warrant consideration of a diagnosis of PWS; neither did they obtain a positive score according to Holm et al.'s criteria.
Conclusion:
PWS was confirmed in only 35% of South African patients with a putative PWS diagnosis, confirming that this condition is overdiagnosed and that the clinical diagnosis is difficult. Clinically, the diagnostic criteria of Holm et al. are of great assistance in making the diagnosis, but it remains essential to confirm the diagnosis by molecular analysis.