Components of an Effective Large Scale Program for the Prevention of Inherited Hemoglobin Disorders; the Paradigm of Greece

Abstract

Large scale prevention programs for Thalassemia major or Sickle cell disease have already been set up in several places with high frequency of the deleterious genes. The Greek health authorities realized the magnitude of the problem and allowed the creation of a National Thalassemia Center in 1972. The incidence of thalassemia in Greece varies from 1–2 per cent up to 15%, the mean being around 8 per cent. With an annual number of births around 100,000, if no prevention measures are taken, the expected yearly number of newborns with thalassemia major in Greece should be of the order of 100–120. To these one should add a few decades of sickle cell patients, homozygotes or compound HbS/β-thalassemia heterozygotes. The total number of patients with thalassemia major now surviving is estimated at 4000 plus another 600–800 patients with sickle cell disease. The National Thalassemia Center Center defined a network of peripheral Thalassemia Units in the major regional hospitals of the country, let them provide free carrier identification to couples requesting the test. When both partners were identified as carriers, they were given preliminary information locally and were referred to the Central Laboratory in Athens for further genetic counselling and, if so decided, prenatal diagnosis. Prenatal diagnosis was provided initially by fetoscopy and fetal blood biosynthesis; this approach was soon replaced by chorionic villi sampling and molecular techniques. The number of prenatal diagnoses carried out yearly over the last decade appears to cover the needs; the number of positive diagnoses is very close to the expected 25%, which also excludes overdiagnosis. The overall evaluation of the the program is reflected in the number of infants who were admitted to the pediatric clinics of the country in need of transfusion over the years the program was functioning. In fact, over the past years this number has steadily decreased to approximately 10 missed diagnoses annually, but has not reached zero as expected, after all this effort. The function of a comprehensive program for the prevention of thalassemia and HbS disease in Greece over the last 25 years has helped enormously in (a) avoiding birth of several hundreds of children with thalassemia major, thus (b) securing the use of the available resources for the optimal care of the patients who are living to-day, and (c) allowing thousands of couples at risk to give birth to healthy children.