Two independent de novo mutations as a cause for neurofibromatosis type 1 and Noonan syndrome in a single family.

Here we report on a family with two siblings born to unrelated healthy parents, one with neurofibromatosis type 1 (NF1) and the other with Noonan syndrome (NS). Molecular investigations performed on the NF1 and PTPN11 genes showed two independent de novo mutations as a cause for NF1 in the NF1 proband and NS in her affected brother. Both de novo mutations were potentially of paternal origin, given the advanced paternal age at the time of conception.