Tuberous sclerosis. Diagnostic problems in a family.

This paper describes a family in which the first child, a girl born in 1988, has tuberous sclerosis (TS). The 28-year-old mother had no symptoms of TS but at ocular examination she presented with progressively increasing prominence of the optic nerve heads with a few glistening spots due to deep and superficial drusen, and tilted disks. Visual fields showed enlarged blind spots. Fluorescein angiography showed lobular drusen of the optic nerve heads. The ERG showed an absent B-wave. The family history was negative for TS. The question arises whether these ocular findings have to be interpreted as part of the syndrome of TS. In that case the recurrence risk for the disease is 50% for each next child. Assuming a spontaneous mutation in the first child, however, the risk can be nearly neglected. Until the genetic defect in TS is found, these problems in genetic counselling of parents with a child with TS will remain unsolved. Prenatal diagnosis by DNA-analysis is not yet possible; however a few cases of TS have been diagnosed prenatally by fetal ultrasonography of the heart, as was the case in the affected child.