Protein C deficiency Hong Kong 1 and 2: hereditary protein C deficiency caused by two mutant alleles, a 5-nucleotide deletion and a missense mutation.
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Sugahara Y, Miura O, Yuen P, Aoki N
Protein C deficiency Hong Kong 1 and 2: hereditary protein C deficiency caused by two mutant alleles, a 5-nucleotide deletion and a missense mutation.
Blood. 1992 Jul 1;80(1):126-33.
- PubMed ID
- 1611081 [ View in PubMed]
- Abstract
We characterized a mutant protein C gene from an individual with no detectable protein C antigen in blood plasma. Southern blot hybridization analysis with human protein C cDNA demonstrated neither gross deletion nor rearrangement of the gene. Sequencing all the exons and exon-intron boundaries of the gene except the 3' noncoding region showed two mutant alleles. The one, derived from the mother, represents a deletion of 5 nucleotides (nt) (CCCGC) in the end of exon VI (mutation I), predicted to result in the generation of a new stop codon due to a reading frameshift and the premature termination of translation. The other, derived from the father, represents a point mutation (G to A) in exon IX (mutation II), resulting in an amino acid substitution, Gly-376(GGC) to Asp(GAC), in the catalytic domain of the protein. Allele-specific oligonucleotide probe hybridization confirmed the presence of the two mutations. Mutation I would result in a truncated polypeptide of 169 amino acid residues that lacks the heavy chain. Mutation II gives rise to an alteration of a highly conserved amino acid, Gly-376. These data indicate that this patient is a compound heterozygote of the two mutant alleles, each one inherited from each parent. Transient expression assays using COS-7 cells transfected with mutated protein C expression vectors suggested that each of the two mutations leads to the protein C deficiency by causing an impairment of secretion of the respective mutant proteins.