FN1 and Bloom syndrome: Furthermore, BLM treatment increased expression levels of the ECM genes Col1a1, Col3a1, and Fn, and these levels showed a trend of further increase in heterozygous and homozygous mice treated with BLM as compared with wild-type mice treated similarly (Figure 8C–E), suggesting that hIGFBP-5 transgene expression potentiated the response to BLM.