Federica Alberti

Quantitative assessment of minimal residual disease in acute myeloid leukemia carrying nucleophosmin (NPM1) gene mutations

Mutations in exon 12 of the nucleophosmin (NPM1) gene occur in about 60% of adult AML with normal karyotype. By exploiting a specific feature of NPM1 mutants, that is insertion at residue 956 or deletion/insertion at residue 960, we developed highly sensitive, real-time quantitative (RQ) polymerase chain reaction (PCR) assays, either in DNA or RNA, that are specific for various NPM1 mutations. In all 13 AML patients carrying NPM1 mutations at diagnosis, cDNA RQ-PCR showed >30 000 copies of NPM1-mutated transcript. A small or no decrease in copies was observed in three patients showing partial or no response to induction therapy. The number of NPM1-mutated copies was markedly reduced in 10 patients achieving complete hematological remission (five cases: <100 copies; five cases: 580–5046 copies). In four patients studied at different time intervals, the number of NPM1 copies closely correlated with clinical status and predicted impending hematological relapse in two. Thus, reliable, sensitive RQ-PCR assays for NPM1 mutations can now monitor and quantify MRD in AML patients with normal karyotype and NPM1 gene mutations.

Natural history of juvenile haemochromatosis

Summary. Juvenile haemochromatosis or haemochromatosis type 2 is a rare autosomal recessive disorder which causes iron overload at a young age, affects both sexes equally and is characterized by a prevalence of hypogonadism and cardiopathy. Patients with haemochromatosis type 2 have been reported in different ethnic groups. Linkage to chromosome 1q has been established recently, but the gene remains unknown. We report the analysis of the phenotype of 29 patients from 20 families of different ethnic origin with a juvenile 1q‐associated disease. We also compared the clinical expression of 26 juvenile haemochromatosis patients with that of 93 C282Y homozygous males and of 11 subjects with haemochromatosis type 3. Patients with haemochromatosis type 2 were statistically younger at presentation and had a more severe iron burden than C282Y homozygotes and haemochromatosis type 3 patients. They were more frequently affected by cardiopathy, hypogonadism and reduced glucose tolerance. In contrast cirrhosis was not statistically different among the three groups. These data suggest that the rapid iron accumulation in haemochromatosis type 2 causes preferential tissue damage. Our results clarify the natural history of the disease and are compatible with the hypothesis that the HFE2 gene has greater influence on iron absorption than other haemochromatosis‐associated genes.