Tuberous sclerosis in a child with de novo translocation t(3;12) (p26.3;q23.3).

We report on an 8-year-old boy with severe mental retardation, epileptic seizures, autistic behaviour, and X-ray CT findings of the skull characteristic for tuberous sclerosis. At the age of 9 years, first signs of adenoma sebaceum developed. Chromosomal analysis revealed a translocation t(3; 12) (p26.3;q23.3). The parents were both healthy and had normal karyotypes. As non-random association of a chromosomal abnormality and tuberous sclerosis is hypothesized, a third locus for this disorder on 3p26 or 12q23 has to be taken in account.