Rapid diagnosis of alpha-thalassemia-1 of southeast Asia type and hydrops fetalis by polymerase chain reaction [letter]

Homozygous alpha-thalassemia associated with hypospadias in three survivors

“…At 22 weeks of gestation, the fetus was found to suffer from hydrops fetalis. The parents are ␣TH carriers, i.e., heterozygotes for SEA-type, as detected by polymerase chain reaction-based DNA analysis according to the method of Chang et al [1991]. Fetal blood examinations (hemoglobin level, 9.6g/dl with 74% of hemoglobin Barts, and 26% of hemoglobin Portland) and DNA analysis confirmed that the patient had ␣TH with homozygous SEA-type deletions.…”

Sensitivity and specificity of mean corpuscular volume testing for screening for α‐thalassemia‐1 and β‐thalassemia traits

“…The hemoglobin A2 (HbA2) level and polymerase chain reaction (PCR) for the a -thalassemia-1 gene (South-East Asia [SEA] type) were measured in all cases as a gold standard for detecting b -thalassemia and a -thalassemia-1 traits, respectively. [6][7][8] HbA2 levels of 4.1-9.0% and positive PCR for the SEA type were used to diagnose b -thalassemia and a -thalassemia-1 traits, respectively. The identification of any bthalassemia or a -thalassemia-1 traits was considered abnormal, or a positive final diagnosis.…”

Quantitative polmerase chain reaction for the rapid prenatal diagnosis of homozygous α‐thalassaemia (Hb Barts hydrops fetalis)

“…Prenatal diagnosis of homozygous a8-thal is usually performed by detection of a-genes in fetal DNA using Southern blot analysis (Chan et al, 1984). Recently, polymerase chain reaction (PCR) amplification of the normal and a8-thal chromosomes (Cai et al, 1989;Chang et al, 1991;Ko et al, 1992;Winichagoon et al, 1995) enabled diagnosis to be made more rapidly. However, misdiagnosis using PCR can occur either with contamination of maternal DNA in the chorionic villi (CV), or as a result of allelic dropout (Chan & Chan, 1997;Ko et al, 1997).…”