A new in-frame deletion in ribosomal protein S19 in a Chinese infant with Diamond-Blackfan anemia.

Diamond-Blackfan anemia (DBA) is a congenital erythroid aplasia that usually presents as macrocytic anemia during infancy. Ribosomal protein S19 (RPS19) is identified as the first gene associated with DBA. RPS19 is mutated in 25% of DBA patients, but its role in DBA pathogenesis remains to be elucidated. We have identified a novel heterozygous frameshift mutation in RPS19 gene in a DBA child presenting with profound anemia after birth. A single nucleotide heterozygous deletion (C.251delG) results in frameshift in RPS19 gene in exon 4 at codon 84 with possible premature stop codon (p.Arg84LysfsX21). The mutant allele was not detected in her parents, indicating de novo mutation. Both alleles were expressed at the same level. Using an immunofluorescence technique, the mutated-type RPS19 expressions were mostly localized to entire nuclei with little staining for nucleoli and its intracellular localization significantly differed from the wild-type RPS19, which was localized to both nuclei and nucleoli. This type of a mutation could be very helpful in further understanding the role of the RPS19 protein in DBA pathogenesis.