DIAGNOSIS OF BLOOM-SYNDROME BY SISTER-CHROMATID EXCHANGE EVALUATION IN CHORIONIC VILLUS CULTURES

Cultures of a chorion biopsy taken from a pregnancy at risk of Bloom's syndrome revealed the high sister chromatid exchange frequency diagnostic of this rare disorder. To obtain the result, cultures were grown-under standard conditions, with the addition of 10 mu M 5'-bromodeoxyuridine for the final 48 h of incubation. This result demonstrates the feasibility of early prenatal diagnosis of Bloom's syndrome.