[Incontinentia pigmenti. Study of 3 families].

Ten cases of incontinentia pigmenti are reported. All patients, corresponding to three families, were female. In one case a Turner's syndrome phenotype (XO) with mosaicism 46 XX/46 X; i (Xq) was observed. This finding seems to confirm that the disease is transmitted through a dominant gene carried on the X chromosome. Dental alterations were the most frequent of associated abnormalities, being present in all 10 patients. We regard these abnormalities as important as they permit a retrospective diagnosis in adult patients after the skin lesions have disappeared. EEG alterations (essentially an increase in the slow component) were also observed in the majority of cases.