First de novo mutations in the protein C gene of two patients with type I deficiency: a missense mutation and a splice site deletion

Abstract In a series of 40 patients with symptomatic protein C deficiency, we identified two sporadic cases with novel mutations that probably affect gene expression. The mutations, a 5-bp deletion of the donor splice site of intron f (nucleotides 3455 to 3459) and a mutation of nucleotide 8523 in exon IX leading to the substitution of Ser 270 by Pro, were not found in the protein C gene of the patients' parents. Transmission of the paternal and maternal protein C alleles was apparently normal on the basis of frequent polymorphisms in exons I, VI, and VIII. We also checked the transmission of the chromosomal material by analyzing the beta-globin gene frameworks and three variable number of tandem repeats (VNTRs). By combining the results of intragenic polymorphism, VNTR and beta-globin gene framework analyses, we were able to exclude nonpaternity and confirm the de novo origin of the mutation.

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First de novo mutations in the protein C gene of two patients with type I deficiency: a missense mutation and a splice site deletion

Blood ◽

10.1182/blood.v84.8.2566.bloodjournal8482566 ◽

1994 ◽

Vol 84 (8) ◽

pp. 2566-2570

Author(s):

S Gandrille ◽

B Jude ◽

M Alhenc-Gelas ◽

J Emmerich ◽

M Aiach

Keyword(s):

Splice Site ◽

Protein C ◽

Tandem Repeats ◽

De Novo ◽

Globin Gene ◽

Type I ◽

Beta Globin ◽

De Novo Mutations ◽

Protein C Deficiency ◽

Beta Globin Gene

In a series of 40 patients with symptomatic protein C deficiency, we identified two sporadic cases with novel mutations that probably affect gene expression. The mutations, a 5-bp deletion of the donor splice site of intron f (nucleotides 3455 to 3459) and a mutation of nucleotide 8523 in exon IX leading to the substitution of Ser 270 by Pro, were not found in the protein C gene of the patients' parents. Transmission of the paternal and maternal protein C alleles was apparently normal on the basis of frequent polymorphisms in exons I, VI, and VIII. We also checked the transmission of the chromosomal material by analyzing the beta-globin gene frameworks and three variable number of tandem repeats (VNTRs). By combining the results of intragenic polymorphism, VNTR and beta-globin gene framework analyses, we were able to exclude nonpaternity and confirm the de novo origin of the mutation.

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Ectopic Transcript Analysis Indicates that Allelic Exclusion is an Important Cause of Type I Protein C Deficiency in Patients with Nonsense and Frameshift Mutations in the PROC Gene

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650386 ◽

1996 ◽

Vol 75 (06) ◽

pp. 870-876 ◽

Cited By ~ 4

Author(s):

José Manuel Soria ◽

Lutz-Peter Berg ◽

Jordi Fontcuberta ◽

Vijay V Kakkar ◽

Xavier Estivill ◽

...

Keyword(s):

Splice Site ◽

Protein C ◽

Stop Codon ◽

Premature Stop Codon ◽

Allelic Exclusion ◽

Polymorphism Analysis ◽

Type I ◽

Protein C Deficiency ◽

Nonsense Mutations ◽

Stop Codons

SummaryNonsense mutations, deletions and splice site mutations are a common cause of type I protein C deficiency. Either directly or indirectly by altering the reading frame, these' lesions generate or may generate premature stop codons and could therefore be expected to result in premature termination of translation. In this study, the possibility that such mutations could instead exert their pathological effects at an earlier stage in the expression pathway, through “allelic exclusion” at the RNA level, was investigated. Protein C (PROC) mRNA was analysed in seven Spanish type I protein C deficient patients heterozygous for two nonsense mutations, a 7bp deletion, a 2bp insertion and three splice site mutations. Ectopic RNA transcripts from patient and control lymphocytes were analysed by RT-PCR and direct sequencing of amplified PROC cDNA fragments. The nonsense mutations and the deletion were absent from the cDNAs indicating that only mRNA derived from the normal allele had been expressed. Similarly for the splice site mutations, only normal PROC cDNAs were obtained. In one case, exclusion of the mutated allele could be confirmed by polymorphism analysis. In contrast to these six mutations, the 2 bp insertion was not associated with loss of mRNA from the mutated allele. In this case, cDNA analysis revealed the absence of 19 bases from the PROC mRNA consistent with the generation and utilization of a cryptic splice site 3’ to the site of mutation, which would result in a frameshift and a premature stop codon. It is concluded that allelic exclusion is a common causative mechanism in those cases of type I protein C deficiency which result from mutations that introduce premature stop codons

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Italian type of deletional hereditary persistence of fetal hemoglobin

Blood ◽

10.1182/blood.v68.3.646.646 ◽

1986 ◽

Vol 68 (3) ◽

pp. 646-651 ◽

Cited By ~ 25

Author(s):

G Saglio ◽

C Camaschella ◽

A Serra ◽

T Bertero ◽

G Rege Cambrin ◽

...

Keyword(s):

Globin Gene ◽

Fetal Hemoglobin ◽

Type I ◽

Italian Population ◽

Beta Globin ◽

Beta Globin Gene ◽

Gamma Globin ◽

New Type ◽

Hereditary Persistence ◽

Chain Synthesis

Abstract We report a new type of deletion of the beta globin gene cluster in the Italian population that confers a phenotype of hereditary persistence of fetal hemoglobin (HPFH) to the carriers. This deletion begins approximately 5 kilobases (kb) 5′ to the delta globin gene and ends approximately 30 kb 3′ to the beta globin gene, in close proximity to the 3′ end of an Indian HPFH. In all four previously described HPFH, a repetitive Alu I region 5′ to the delta globin gene is largely or completely deleted; the 5′ end of the new HPFH is consistent with this common feature. In addition, the finding that Italian and Indian HPFHs, as reported for other groups of deletions, have very close 3′ ends, strengthens the idea that common mechanisms may operate in generating these deletions. Finally, we show that, in spite of similar 5′ breakpoints, the deletion of Spanish delta beta degrees-thalassemia is at least 8 kb longer than that of Negro HPFH type I, thus ruling out the hypothesis that the overall extent of the deletion might influence the level of gamma globin chain synthesis.

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Italian type of deletional hereditary persistence of fetal hemoglobin

Blood ◽

10.1182/blood.v68.3.646.bloodjournal683646 ◽

1986 ◽

Vol 68 (3) ◽

pp. 646-651

Author(s):

G Saglio ◽

C Camaschella ◽

A Serra ◽

T Bertero ◽

G Rege Cambrin ◽

...

Keyword(s):

Globin Gene ◽

Fetal Hemoglobin ◽

Type I ◽

Italian Population ◽

Beta Globin ◽

Beta Globin Gene ◽

Gamma Globin ◽

New Type ◽

Hereditary Persistence ◽

Chain Synthesis

We report a new type of deletion of the beta globin gene cluster in the Italian population that confers a phenotype of hereditary persistence of fetal hemoglobin (HPFH) to the carriers. This deletion begins approximately 5 kilobases (kb) 5′ to the delta globin gene and ends approximately 30 kb 3′ to the beta globin gene, in close proximity to the 3′ end of an Indian HPFH. In all four previously described HPFH, a repetitive Alu I region 5′ to the delta globin gene is largely or completely deleted; the 5′ end of the new HPFH is consistent with this common feature. In addition, the finding that Italian and Indian HPFHs, as reported for other groups of deletions, have very close 3′ ends, strengthens the idea that common mechanisms may operate in generating these deletions. Finally, we show that, in spite of similar 5′ breakpoints, the deletion of Spanish delta beta degrees-thalassemia is at least 8 kb longer than that of Negro HPFH type I, thus ruling out the hypothesis that the overall extent of the deletion might influence the level of gamma globin chain synthesis.

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Beta-thalassemia due to two novel nucleotide substitutions in consensus acceptor splice sequences of the beta-globin gene

Blood ◽

10.1182/blood.v73.4.914.bloodjournal734914 ◽

1989 ◽

Vol 73 (4) ◽

pp. 914-918

Author(s):

C Wong ◽

SE Antonarakis ◽

SC Goff ◽

SH Orkin ◽

BG Forget ◽

...

Keyword(s):

Splice Site ◽

Rna Splicing ◽

Globin Gene ◽

Beta Thalassemia ◽

Beta Globin ◽

Nucleotide Substitutions ◽

Splice Site Selection ◽

Exon 2 ◽

Consensus Sequences ◽

Beta Globin Gene

We have identified two novel RNA-splicing mutations affecting a critical nucleotide (nt) in the acceptor consensus sequences at both the IVS-1/exon 2 and IVS-2/exon 3 junctions of the human beta-globin gene. Both mutations are single nt substitutions, T to G and C to A, at position -3 adjacent to the invariant AG dinucleotide. For the IVS- 2/exon 3 mutation abnormal splicing into the cryptic splice site at IVS- 2 nt 579 is documented. Identification of these two mutations provides further support for the importance of the location of specific nucleotides within the consensus sequences in splice site selection and RNA processing.

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Gamma delta beta-thalassemia due to a de novo mutation deleting the 5' beta-globin gene activation-region hypersensitive sites.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.86.19.7470 ◽

1989 ◽

Vol 86 (19) ◽

pp. 7470-7474 ◽

Cited By ~ 129

Author(s):

M. C. Driscoll ◽

C. S. Dobkin ◽

B. P. Alter

Keyword(s):

De Novo ◽

Globin Gene ◽

Gene Activation ◽

De Novo Mutation ◽

Beta Thalassemia ◽

Beta Globin ◽

Gamma Delta ◽

Beta Globin Gene ◽

Hypersensitive Sites

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Beta-thalassemia due to two novel nucleotide substitutions in consensus acceptor splice sequences of the beta-globin gene

Blood ◽

10.1182/blood.v73.4.914.914 ◽

1989 ◽

Vol 73 (4) ◽

pp. 914-918 ◽

Cited By ~ 49

Author(s):

C Wong ◽

SE Antonarakis ◽

SC Goff ◽

SH Orkin ◽

BG Forget ◽

...

Keyword(s):

Splice Site ◽

Rna Splicing ◽

Globin Gene ◽

Beta Thalassemia ◽

Beta Globin ◽

Nucleotide Substitutions ◽

Splice Site Selection ◽

Exon 2 ◽

Consensus Sequences ◽

Beta Globin Gene

Abstract We have identified two novel RNA-splicing mutations affecting a critical nucleotide (nt) in the acceptor consensus sequences at both the IVS-1/exon 2 and IVS-2/exon 3 junctions of the human beta-globin gene. Both mutations are single nt substitutions, T to G and C to A, at position -3 adjacent to the invariant AG dinucleotide. For the IVS- 2/exon 3 mutation abnormal splicing into the cryptic splice site at IVS- 2 nt 579 is documented. Identification of these two mutations provides further support for the importance of the location of specific nucleotides within the consensus sequences in splice site selection and RNA processing.

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