Hydrops fetalis in three male fetuses of a female with incontinentia pigmenti

Objectives Careful investigation of hydrops fetalis (HF) is important with regard to genetic counselling and prenatal diagnosis. HF is known to be associated with various genetic disorders. To date there has been only one report of a male fetus in whom incontinentia pigmenti (IP) was associated. with generalised oedema. We describe a family who had a girl with clinical signs of IP after three consecutive miscarriages of three male fetuses due to HF. Results Molecular genetic analysis showed a mutation in the NEMO/IKK% gene in the girl and the mother, which confirmed the diagnosis of IP in both cases. In the two fetuses that could be investigated, inheritance of the affected maternal X chromosome could be demonstrated retrospectively by linkage analysis. Conclusion The present findings suggest that IP might be an X-linked dominant trait causing HF in male fetuses. In cases of recurrent HF in male fetuses, minimal signs of IP in the maternal line should therefore be carefully investigated in order to be able to perform mutational analysis and to offer appropriate genetic counselling. Copyright (C) 2001 John Wiley & Sons, Ltd.