Results of screening of cord blood samples from 5605 newborns for α thalassaemia and blood samples from 7792 adults for β thalassaemia in Guangdong Province
| Variable | Number of samples or alleles | Per cent |
|---|---|---|
| *The number of carriers with both deletional and non-deletional mutations and patients with hydrops fetalis and Hb H disease; †novel mutations found during our survey. | ||
| Samples with Hb Bart’s | 371 | 6.62 |
| α Thalassaemia* | 340 | – |
| Normal | 29 | – |
| Undetermined | 2 | – |
| Silent carriers without Hb Bart’s | 129 | 2.30 |
| (−α3.7) Deletion | 102 | – |
| (−α4.2) Deletion | 27 | – |
| α Thalassaemia chromosomes | 478 | 8.53 |
| (−−SEA) Deletion | 232 | 4.14 |
| (−α3.7) Deletion | 174 | 3.10 |
| (−α4.2) Deletion | 53 | 0.95 |
| (−αCS) Mutation | 10 | 0.18 |
| (−−THAI) Deletion | 2 | 0.04 |
| (−αQS) Mutation | 2 | 0.04 |
| (−−11.1) Deletion† | 1 | 0.02 |
| α1CD118 (+TCA)† | 1 | 0.02 |
| ζ-α Gene deletion | 1 | 0.02 |
| Undetermined | 2 | 0.04 |
| β Thalassaemia chromosomes | 198 | 2.54 |
| Deletion of CTTT at codons 41–42 | 72 | 0.92 |
| C→T at position 654 in IVS2 | 49 | 0.63 |
| A→G at nucleotide −28 | 33 | 0.42 |
| G→A at codon 26 (Hb E) | 10 | 0.13 |
| A→T at codon 17 | 8 | 0.10 |
| Insertion of A at codons 71–72 | 7 | 0.09 |
| G→T at codon 43 | 7 | 0.09 |
| A→G at nucleotide −29 | 4 | 0.05 |
| Insertion of A at codons 27–28 | 4 | 0.05 |
| β Gene deletion† | 1 | 0.01 |
| Undetermined | 3 | 0.04 |