RESUMEN
Beckwith-Wiedemann syndrome (BWS) is a genetic disease with phenotypic variability and the following signs: macroglossia, asymmetry, lateralised overgrowth, overgrowth of the internal organs, abdominal wall defects, neonatal hypoglycemia and increased risk of embryonic tumours. The prevalence is reported as being between 1 in 10,000 and 1 in 21,000 live births. The disease is caused by molecular changes in gene clusters on the short arm of chromosome 11 region P15.5. We present the case of a female, born preterm at 32 0/7 weeks. A UPD(11)pat-mutation was diagnosed postnatally. The particular feature of her case was an early tongue reduction surgery which was necessary because of drinking and breathing difficulties. Long-lasting hypoglycemia was difficult to treat.