[show abstract][hide abstract] ABSTRACT: Thalassaemia is a good candidate disease for control by preventive genetic programmes in developing countries. Accurate population frequency data are needed for planning the control of thalassaemia in the high risk Guangdong Province of southern China.
In total, 13397 consecutive samples from five geographical areas of Guangdong Province were analysed for both haematological and molecular parameters.
There was a high prevalence of carriers of alpha thalassaemia (8.53%), beta thalassaemia (2.54%), and both alpha and beta thalassaemia (0.26%). Overall, 11.07% of the population in this area were heterozygous carriers of alpha and beta thalassaemia. The mutation spectrum of alpha and beta thalassaemia and its constitution were fully described in this area. This study reports the true prevalence of silent alpha thalassaemia in the southern China population for the first time. In addition, two novel mutations that give rise to alpha thalassaemia, one deletion resulting in beta thalassaemia, and a rare deletion (--(THAI) allele) previously unreported in mainland China were detected. The frequency of the most common mutation, the Southeast Asian type of deletion (--(SEA), accounting for 48.54% of all alpha thalassaemias) was similar to the total of two alpha(+) thalassaemia deletions (-alpha(3.7) and -alpha(4.2), accounting for 47.49% of alpha thalassaemia).
Both alpha and beta thalassaemia are widely distributed in Guangdong Province of China. The knowledge gained in this study will enable the projected number of pregnancies at risk to be estimated and a screening strategy for control of thalassaemia to be designed in this area.
Journal of Clinical Pathology 06/2004; 57(5):517-22. · 2.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the efficacy of various sonographic markers at midpregnancy in predicting fetal hemoglobin Bart disease.
Four hundred eighty-eight pregnancies at risk of having fetuses with hemoglobin Bart disease were recruited for prenatal diagnosis with cordocentesis at 18 to 21 gestational weeks. Before cordocentesis, the sonographic markers, including cardiothoracic ratio, placental thickness, pericardial effusion, pleural effusion, ascites, subcutaneous edema, cord edema, dilated umbilical vein, and amniotic fluid index, were assessed and recorded. The definite fetal diagnosis was based on blood analysis. The efficacy of each sonographic marker in predicting hemoglobin Bart disease was evaluated by sensitivity and specificity.
Among 488 pregnancies undergoing prenatal diagnosis, 100 fetuses were proved to be affected by hemoglobin Bart disease. The cardiothoracic ratio gave the highest sensitivity, 95.0%, with specificity of 96.1%, followed by placental thickness. Signs of hydrops fetalis were observed in 33.0% of cases; they did not increase the sensitivity of the cardiothoracic ratio but strongly reinforced the diagnosis when they appeared.
At midpregnancy, sonographic markers can effectively differentiate normal pregnancies from those with fetal hemoglobin Bart disease. Among couples at risk with no sonographic markers, the risk of having an affected child is nearly eliminated. The most sensitive marker was the cardiothoracic ratio, followed by placental thickness.
Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 02/2004; 23(1):49-55. · 1.40 Impact Factor
[show abstract][hide abstract] ABSTRACT: We determined the feasibility of prenatal prediction of type 1 homozygous alpha-thalassemia at 12 to 13 weeks of gestation by either abdominal or vaginal (or both) ultrasonographic examination to measure the fetal cardiothoracic ratio in 135 at-risk pregnancies. Forty-three fetuses were affected by homozygous type 1 alpha-thalassemia. The mean cardiothoracic ratio was significantly larger than that of the unaffected fetuses (0.54 vs 0.45, P <.0005), with no overlap between the 2 groups. A cardiothoracic ratio cutoff point of >/=0.5 was 100% sensitive and specific for disease.
American Journal of Obstetrics and Gynecology 02/1999; 180(1 Pt 1):148-50. · 3.88 Impact Factor
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