MUTATION | Codon 67 (-TG); GTG(Val)->--G | ||
---|---|---|---|
AMINO ACID REPLACEMENT | None | ||
TYPE OF BETA-THAL | beta° | ||
MECHANISM | The loss of the two nucleotides causes a frameshift with a stop codon at the new codon 71 (TAG) resulting in a premature termination of translation | ||
IDENTIFICATION | Amplification of the beta-globin gene; DNA sequencing | ||
HEMATOLOGY IN HETEROZYGOTE(S) | Hb 10.7-11.5 g/dl; MCV 59-64 fl; Hb A2 4.8-6.6%; Hb F 0.6-1.4% | ||
HEMATOLOGY IN HOMOZYGOTE(S) | Not reported | ||
OCCURRENCE | In a Filipino family | ||
HAPLOTYPE | Not reported | ||
FOUND IN COMBINATION WITH ABNORMAL HB(S) | None | ||
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) | The proband is a child with severe beta-thal major who is a compound heterozygote for this frameshift and a second beta-thal allele which involves the deletion of the entire beta-globin gene; hematology at 9 months: Hb 6.2 g/dl; MCV 74.1 fl; Hb A2 2.5%; Hb F 97.5% | ||
OTHER INFORMATION | None |
REFERENCES | |||
1. | Eng, B., Chui, D.H.K., Saunderson, J., Olivieri, N.F., and Waye, J.S.: Hum. Mutat., 2:374, 1993. |