Familial fragile site found at the cancer breakpoint (1)(q32). Inducibility by distamycin A, concomitance with fragile (16)(q22).

A normal baby was cytogenetically examined immediately after birth for the possible presence of a fragile (16)(q22), which had been found in her mother and in her retarded sister with a 46,XX;46,XX,del(16)(q22) mosaic karyotype. Distamycin A was added to the cultures to enhance the fragile (16)(q22) expression. The response of the baby to the action of distamycin A in vitro was much greater than that of her family members. A fragile (16)(q22) was induced in many cells as well as a fragile (1)(q32), which was also found in her mother. This fragile site, which is known to be a cancer breakpoint, has not been reported so far either to be familial or to be inducible by distamycin A. The concomitance of fragile (1)(q32) with fragile (16)(q22) and their possible significance are considered.