We report the first case of prenatal diagnosis of Stickler syndrome in a child with a Pierre-Robin sequence (PRS) causing a polyhydrammos. When isolated polyhydrammos is not explained by immunological, metabolic or infectious causes, swallowing difficulty due to PRS must be considered. As PRS is aetiologically heterogenous, the prognosis depends on the cause. Genetic investigations and familial history must be taken into account. Here, in a context of familial Stickler syndrome, making the prenatal diagnosis of PRS as part of Stickler syndrome allowed us to reassure the parents and to anticipate airway trouble at the child's birth. Copyright (C) 2002 John Wiley Sons, Ltd.