Sir.—A 28-year-old gravida II, para I woman was referred for genetic counseling because of a Wilms' tumor in her previous child. Her daughter had been born at term, weighed 4.2 kg, and had a purplish birthmark over her forehead. Her neonatal course was uncomplicated. At age 1 year, her left leg and foot were found to be smaller than the right. At age 5 years, the finding of a large abdominal mass during a routine examination led to the diagnosis of bilateral Wilms' tumor. At age 9 years, the girl weighed 65 kg, was 139 cm tall, and had a faint fan-shaped midline nevus flammeus on her forehead. She had mild macroglossia but no dental malocclusion, earlobe creases, umbilical hernia, or diastasis recti. Her left foot was 1.5 cm shorter than the right. Her mother was 174 cm tall, weighed 122 kg, and had diastema between her upper central