Factor IX Chongqing: a new mutation in the calcium-binding domain of factor IX resulting in severe hemophilia B.

Article Details

Citation

Wang NS, Zhang M, Thompson AR, Chen SH

Factor IX Chongqing: a new mutation in the calcium-binding domain of factor IX resulting in severe hemophilia B.

Thromb Haemost. 1990 Feb 19;63(1):24-6.

PubMed ID
2339358 [ View in PubMed
]
Abstract

A Chinese patient with sporadic, severe hemophilia B was found to have a low level of total factor IX antigen (3.5 U/dl), but less apparent antigen in an assay using a calcium-dependent antibody fraction (1.1 U/dl). This suggested a defect in the factor IX Gla domain coded mainly by exon 2 of the factor IX gene. Exon 2 was therefore amplified and sequenced. An A to T substitution was found at nucleotide 6455 of the patient's factor IX gene. This transversion changes the codon for Glu 27 in normal factor IX to a codon for Val. Since Glu 27 becomes an essential Gla residue, the defect should result in altered calcium-binding or calcium-dependent conformation of the patient's factor IX. The introduction of a hydrophobic side chain also appears to affect the hemophilic protein's stability. In leukocyte DNA from the patient's mother, the nucleotide sequence of exon 2 was entirely normal. Thus, barring somatic mosaicism within her germ cells, the new mutation occurred in oogenesis of her ovary.

DrugBank Data that Cites this Article

Polypeptides
NameUniProt ID
Coagulation factor IXP00740Details