Frequency of congenital dyserythropoietic anemias in Europe.

Congenital dyserythropoietic anemias (CDAs) are rare hereditary disorders characterized by ineffective erythropoiesis and striking abnormalities of erythroblast morphology. The mutated genes are known for the most frequent types, CDA I and II, but data about their frequency do not exist. The objective of this retrospective study was to estimate the frequency of CDA I and II, based on all cases reported in the last 42 yr in publications and identified registries or surveys. Reports were collected of 124 and 377 confirmed cases of CDA I and CDA II cases, respectively. The cumulated incidence of both types combined varied widely between European regions, with minimal values of 0.08 cases/million in Scandinavia and 2.60 cases/million in Italy. CDA II is more frequent than CDA I, with an overall ratio of approximately 3.2, but the ratio also varied between different regions. The most likely explanations for the differences are both differences in the availability of advanced diagnostic procedures and different levels of the awareness for the diagnosis of the CDAs. The estimations reported here are most probably below the true incidence rates, because of failure to make the correct diagnosis and to underreporting. Limited data do not suggest differing levels of risk in identified ethnic groups.

Congenital dyserythropoietic anemia type I (CDA I): molecular genetics, clinical appearance, and prognosis based on long-term observation.

Congenital dyserythropoietic anemia type I (CDA I) is a rare autosomal recessive disorder with ineffective erythropoiesis and iron overloading. More than 100 cases have been described, but with the exception of a report on a large Bedouin tribe, these reports include only small numbers of cases, and no data on the lifetime evolution of the disease are available. Since 1967, we have been able to follow 21 cases from 19 families for up to 37 years. Twenty-one patients with a confirmed diagnosis of CDA I exhibited chronic macrocytic anemia of variable severity, requiring regular red cell transfusions only in 2 individuals. Four developed gallstones before the age of 30 years. Fifteen of 16 cases alive at the time of analysis showed mutations of at least one allele from exons 6 to 28 within CDAN1. Iron overloading is to be expected in all patients. In 9 patients, iron depletion was started between the ages of 7 and 36 years. Splenectomy, which was performed in 7 patients, did not result in improvement of hemoglobin values. Five patients were treated with interferon alpha-2a, and all responded with a rise in hemoglobin concentration of between 25 and 35 g/L (2.5 and 3.5 g/dL) starting within 4 weeks.

Quantification of PRV-1 mRNA distinguishes polycythemia vera from secondary erythrocytosis.

To date, the diagnosis of polycythemia vera (PV) relies on clinical criteria. We have recently described the overexpression of a hematopoietic receptor, polycythemia rubra vera-1 (PRV-1), in patients with PV. Here, we report a quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the measurement of PRV-1 mRNA levels. We have determined PRV-1 expression in 71 patients with PV, 11 patients with secondary erythrocytosis (SE), as well as in 80 healthy controls. PV patients express significantly higher amounts of PRV-1 than healthy controls or patients with SE (P <.0001). Because there is no overlap between the PRV-1 expression in PV patients versus healthy controls or SE patients, the assay has a very high sensitivity and specificity for the diagnosis of PV in our population. In patients with erythrocytosis, the quantitative RT-PCR assay described here therefore provides a rapid, highly specific and sensitive tool for the diagnosis of PV.