Simultaneous detection of NPM1 and FLT3-ITD mutations by capillary electrophoresis in acute myeloid leukemia

Mutations in the Nucleophosmin (NPM1) gene have been recently described to occur in about one-third of acute myeloid leukemias (AML) and represent the most frequent genetic alteration currently known in this subset. These mutations generate an elongated NPM1 protein that localizes aberrantly in the cytoplasm. In analogy with Flt3 alterations, NPM1 mutations are mostly detectable in AML with normal karyotype and their recognition may be relevant to identify distinct response to treatment. Hence, in addition to conventional karyotyping and RT-PCR of fusion genes, combined analysis of both Flt3 and NPM1 mutations will be increasingly relevant in the genetic diagnosis work-up of AML. We developed a multiplex RT-PCR assay followed by capillary electrophoresis to simultaneously analyze NPM1 and Flt3 gene alterations (NFmPCR assay). The assay was validated in leukemic cell RNAs extracted from 38 AML patients, which had been previously characterized for Flt3 status by conventional RT-PCR. Direct sequencing of NPM1 RT-PCR products was carried out in 15 cases to verify results obtained by capillary electrophoresis. Both NPM1 sequencing and conventional RT-PCR Flt3 results showed 100% concordance with the results of the NFmPCR assay. We suggest that this assay may be introduced in routine analysis of genetic alterations in AML.

Multiple acyl-CoA-dehydrogenase deficiency (MADD): use of acylcarnitines and fatty acids to monitor the response to dietary treatment

The treatment of multiple acyl-CoA-dehydrogenase deficiency (MADD) includes a low-fat, low-protein, high-carbohydrate diet, avoiding long fasting periods. However, there is no useful biochemical marker to determine the response to different diets or fasting periods. The aims of this study are to report a patient with MADD, diagnosed through a newborn screening program using tandem mass spectrometry, to assess her response to different feedings, and to evaluate the usefulness of acylcarnitines and FFA to monitor the response to dietary changes. The patient was diagnosed at 6 d. Family history revealed three dead siblings. Five tests were performed, one with breast milk and the subsequent four after giving the patient a bottle of a low-fat, low-protein formula (F), F with glucose polymers (GP), F+GP plus uncooked corn starch (CS), or F+GP+CS preceded by amylase. The results showed that acylcarnitines, FFA, and total nonesterified fatty acids levels were greatly improved at 2 and 4 h on F+GP compared with breast milk. At 6 mo of age, the test with F+CS was repeated to assess the response to a longer fast. The results were similar at 2 and 4 h, but showed a marked increase of acylcarnitines, FFA, and total nonesterified fatty acids at 6 h. The increase of these metabolites could not be avoided by the use of F+GP+CS, but was prevented when amylase was used simultaneously. The patient is currently 3.9 y old and has normal growth and development. We conclude that diagnosis of MADD through a newborn screening program using tandem mass spectrometry is suitable; acylcarnitines and FFA are useful to monitor the response to treatment; and exogenous amylase allows the use of CS in small children with MADD. This therapeutic approach may be an alternative to the use of continuous overnight feedings used for young children with severe fatty acid oxidation defects. Early diagnosis and treatment may change the natural history of MADD.