(A) Transmission of a deletion in exon 1 of RPS19 gene in a family with DBA phenotype and isolated high eADA phenotype. The 4-bp deletion found in the first, noncoding exon of RPS19 gene in the DBA proband IV-3 from family F1 was also found in the mother (III-3) and the grandmother (II-5) who presented only with a high eADA phenotype. Other factors are probably involved in this family, because individual III-4 carries the same deletion, but with a strictly normal phenotype, whereas the deletion could not be found in individual II-11, despite an isolated high eADA phenotype. eADA values are expressed as SD from the mean. NA, not available. (B) Partial segregation of a mutation in a DBA family. The acceptor splice site defect of exon 4 was found in the DBA proband III-4, as well as in his father (II-3) presenting with macrocytic anemia. Erythrocyte ADA value measured in the healthy brother III-5 is between +2 and +3 SD, although he does not carry this mutation. eADA values are expressed as SD from the mean. NA, not available.