Impact of early transcranial Doppler screening and intensive therapy on cerebral vasculopathy outcome in a newborn sickle cell anemia cohort.

Transcranial Doppler (TCD) is used to detect children with sickle cell anemia (SCA) who are at risk for stroke, and transfusion programs significantly reduce stroke risk in patients with abnormal TCD. We describe the predictive factors and outcomes of cerebral vasculopathy in the Créteil newborn SCA cohort (n = 217 SS/Sß(0)), who were early and yearly screened with TCD since 1992. Magnetic resonance imaging/magnetic resonance angiography was performed every 2 years after age 5 (or earlier in case of abnormal TCD). A transfusion program was recommended to patients with abnormal TCD and/or stenoses, hydroxyurea to symptomatic patients in absence of macrovasculopathy, and stem cell transplantation to those with human leukocyte antigen-genoidentical donor. Mean follow-up was 7.7 years (1609 patient-years). The cumulative risks by age 18 years were 1.9% (95% confidence interval [95% CI] 0.6%-5.9%) for overt stroke, 29.6% (95% CI 22.8%-38%) for abnormal TCD, which reached a plateau at age 9, whereas they were 22.6% (95% CI 15.0%-33.2%) for stenosis and 37.1% (95% CI 26.3%-50.7%) for silent stroke by age 14. Cumulating all events (stroke, abnormal TCD, stenoses, silent strokes), the cerebral risk by age 14 was 49.9% (95% CI 40.5%-59.3%); the independent predictive factors for cerebral risk were baseline reticulocytes count (hazard ratio 1.003/L × 10(9)/L increase, 95% CI 1.000-1.006; P = .04) and lactate dehydrogenase level (hazard ratio 2.78/1 IU/mL increase, 95% CI1.33-5.81; P = .007). Thus, early TCD screening and intensification therapy allowed the reduction of stroke-risk by age 18 from the previously reported 11% to 1.9%. In contrast, the 50% cumulative cerebral risk suggests the need for more preventive intervention.

Neonatal screening for sickle cell disease in France: evaluation of the selective process.

AIMS: The French national programme for neonatal screening of sickle cell disease is applied to newborns 'at risk', defined as those born to parents originating from sub-Saharan Africa, the Mediterranean area, the Arabic peninsula, the French overseas islands and the Indian subcontinent. The selection is performed by the nurse in charge of blood sampling by interviewing the mother about the family's geographical origins. The mean rate of testing in France is 25%, ranging from 2% to 50% depending on the region. This study aimed to evaluate the effectiveness of selection during this screening programme. METHODS: False-negative cases were identified using two different approaches: first, a regional prospective study aimed at screening all newborns, selected and non-selected, in a restricted area, representing 3% of national births; second, a retrospective national survey to identify false-negative cases. RESULTS: The regional study indicated that selective screening leads to a carrier frequency that is twice as high in the selected population as compared with the non-selected population (1.23% versus 0.62%). The local and national surveys revealed that, during a 6-year period, 28 affected children failed to be selected, leading to a false-negative rate of 2.1%. In contrast to what was expected, most of the cases were due to the failing of the data collection process and not to the misdiagnosis of the risk. CONCLUSIONS: These results show that selective neonatal screening for sickle cell disease is feasible if very careful attention is paid to the selective step.

[A center in Paris for screening and counselling sickle cell patients and carriers]. / Centre d'information et de dépistage de la drépanocytose a Paris.

Prevention of sickle cell anemia, a severe and painful disease, relies on carrier detection and information, and on prenatal diagnosis with the possibility of medical abortion. Here we report the first results of a medical and welfare program launched in Paris 20 months ago and dedicated to sickle cell carrier screening and information.

Evaluation of the Bio-Rad VARIANT II HbA2/HbA1C Dual Program for measurement of hemoglobin concentrations and detection of variants.

In this work data obtained on the VARIANT II hemoglobin analyzer using the Dual Kit elution system were compared to those obtained with the beta-Thalassemia Short Program. Since many laboratories still use an earlier model of the hemoglobin analyzer, the Variant 1, these data were also compared to those obtained with the latter instrument. Our study is divided into two parts. The first is an evaluation of the precision of the VARIANT II for determining the levels of hemoglobin (Hb)A2 and Hb F. This was carried out for normal subjects, thalassemic patients and patients with HbS. The second part concerns the potential of this instrument in the presumptive identification of Hb variants.

[Epidemiology of sickle cell anemia]. / Epidémiologie de la drépanocytose.

In France, 6000-7000 patients are suffering from sickle cell anemia in 2004. The number of patients in continental France exceeds the one found in the overseas regions. The highest frequency is found in the Parisian region where 185-200 new cases are annually diagnosed.