EUFA867 has biallelic FANCA mutations. (A) Introduction of FANCA in EUFA867 lymphoblasts stably expressing FANCM restores FANCD2 monoubiquitination. EUFA867 lymphoblasts were transduced with SF91-FANCM to obtain EUFA867 + FANCM. Subsequently these cells were transduced with bicistronic retroviruses encoding the indicated FA proteins. Cells were treated with 2 mM HU for 16 hours and immunoblotted for FANCD2 and FANCM. (B) EUFA867 has a nonsense mutation 2557C>T (R853X) in FANCA. (C) Mutation IVS7 + 5G>A affects the normal splice donor in FANCA intron 7 and results in a 30-bp insertion of intron 7 sequence in the cDNAs of EUFA867 and her mother. The sequence shown is from an isolated cDNA clone of EUFA867. (D) FANCA cDNA derived from the IVS7 + 5G>A mutation does not correct FANCD2 monoubiquitination. FANCA-deficient HSC72 lymphoblasts were transduced with bicistronic retrovirus encoding either wild-type FANCA or the FANCA mutant derived from the mutation IVS7 + 5G>A. Cells were treated with 1 mM HU to stimulate FANCD2 monoubiquitination.