scholarly journals Somatic mosaicism and compound heterozygosity in female hemophilia B

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1585-1587 ◽  
Author(s):  
Jean-Marc Costa ◽  
Dominique Vidaud ◽  
Ingrid Laurendeau ◽  
Michel Vidaud ◽  
Edith Fressinaud ◽  
...  

Abstract Sequencing the complete factor IX gene of 2 sisters with hemophilia B with different phenotypes and no family history of hemorrhagic diathesis revealed a common 5′ splice site mutation in intron 3 (T6704C) in both and an additional missense mutation (I344T) in one. The presence of dysfunctional antigen in the latter strongly suggested that these mutations are in trans. Neither mutation was found in leukocyte DNA from the asymptomatic parents, but the mother was in somatic mosaicism for the shared splice site mutation. This case illustrates the importance of defining the phenotype and considering somatic mosaicism in sporadic cases. It underlines the limitations of complete gene sequencing for the detection of mosaicism and has implication for genetic counseling.

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1585-1587
Author(s):  
Jean-Marc Costa ◽  
Dominique Vidaud ◽  
Ingrid Laurendeau ◽  
Michel Vidaud ◽  
Edith Fressinaud ◽  
...  

Sequencing the complete factor IX gene of 2 sisters with hemophilia B with different phenotypes and no family history of hemorrhagic diathesis revealed a common 5′ splice site mutation in intron 3 (T6704C) in both and an additional missense mutation (I344T) in one. The presence of dysfunctional antigen in the latter strongly suggested that these mutations are in trans. Neither mutation was found in leukocyte DNA from the asymptomatic parents, but the mother was in somatic mosaicism for the shared splice site mutation. This case illustrates the importance of defining the phenotype and considering somatic mosaicism in sporadic cases. It underlines the limitations of complete gene sequencing for the detection of mosaicism and has implication for genetic counseling.


1995 ◽  
Vol 73 (05) ◽  
pp. 774-778 ◽  
Author(s):  
Marianne Schwartz ◽  
Jørgen Ingerslev ◽  
Elma Scheibel ◽  
Lise Rud Nielsen

SummaryHemophilia B is caused by a wide range of mutations. In order to characterize the mutations among patients in Denmark, we have systematically screened the entire coding region, the promoter region and exon flanking sequences of the gene encoding factor IX using single strand conformation and heteroduplex analyses. Patients from 32 different families were examined, and point mutations (23 different) were found in all of them. Ten of the mutations have not been reported by others; they include a splice site mutation, a single base pair deletion, and missense mutations. Notably, the study contains a female patient and a previously described Leyden mutation. In ten families with sporadic cases of hemophilia B, all 10 mothers were found to be carriers. The origin of two of these mutations was established.


2000 ◽  
Vol 84 (09) ◽  
pp. 449-452 ◽  
Author(s):  
Jane Wyatt ◽  
Stephen May ◽  
Peter George ◽  
Stephen Brennan

SummaryWe investigated the molecular basis of hypofibrinogenaemia in a woman with a history of recurrent, pregnancy-associated bleeding, and miscarriage. She had a Clauss fibrinogen of 0.9 mg/ml and SDS PAGE of purified fibrinogen showed a normal pattern of chains. However careful inspection of reverse phase chain separation profiles showed apparent homozygosity for a more hydrophilic form of the γ chain. DNA Sequencing showed only heterozygosity for a CGT→GGT (Ala→Gly) mutation at codon γ82, but further sequencing showed an additional GT splice sequence mutation at the 5’ end of intron 2 of the γ gene. Translation of mRNA containing this intron would result in premature truncation explaining the phenotypic homozygosity of the γ82 Ala→Gly substitution. The patient’s sister had a mild bleeding disorder with hypofibrinogenaemia and she too was a compound heterozygote for the γ mutations. Her nephew had only the novel splice site mutation, while her mother and daughter inherited only the γ82 Ala→Gly substitution.


Medicina ◽  
2020 ◽  
Vol 56 (9) ◽  
pp. 485
Author(s):  
Magdalena Mrożek ◽  
Ewa Wypasek ◽  
Martine Alhenc-Gelas ◽  
Daniel P. Potaczek ◽  
Anetta Undas

We identified a novel splice site mutation of the PROS1 gene in a Polish family with protein S (PS) deficiency and explored the molecular pathogenesis of this previously undescribed variant. A novel mutation was detected in a 26-year-old woman with a history of venous thromboembolism (VTE) provoked by oral contraceptives. Her family history of VTE was positive. The sequence analysis of the PROS1 gene was performed in the proband and the proband’s family. The proband and their asymptomatic father had lower free PS levels (45% and 50%, respectively) and PS activity (48% and 44%, respectively). Total PS levels were normal (65.6% and 62.4%, respectively). The sequence analysis of the PROS1 gene revealed the presence of heterozygous deletion at the nucleotide position c.602-2 in intron 6, just upstream of exon 7, detected in the proband and her father. This variant alters the splice acceptor site of exon 7, and, according to the in silico prediction, it is highly likely to cause in-frame exon 7 skipping. We also presented follow-up data of two other Polish patients with PS deficiency associated with splice site mutations in PROS1 gene.


2017 ◽  
Vol 48 (S 01) ◽  
pp. S1-S45
Author(s):  
O. Schwartz ◽  
J. Althaus ◽  
B. Fiedler ◽  
K. Heß ◽  
W. Paulus ◽  
...  

2018 ◽  
Vol 70 (5) ◽  
Author(s):  
Melahat M. Oguz ◽  
Meltem Akcaboy ◽  
Asuman Gurkan ◽  
Esma Altinel Acoglu ◽  
Pelin Zorlu ◽  
...  

2021 ◽  
Vol 22 (7) ◽  
pp. 3786
Author(s):  
Andreas Brodehl ◽  
Alexey Meshkov ◽  
Roman Myasnikov ◽  
Anna Kiseleva ◽  
Olga Kulikova ◽  
...  

About 50% of patients with arrhythmogenic cardiomyopathy (ACM) carry a pathogenic or likely pathogenic mutation in the desmosomal genes. However, there is a significant number of patients without positive familial anamnesis. Therefore, the molecular reasons for ACM in these patients are frequently unknown and a genetic contribution might be underestimated. Here, we used a next-generation sequencing (NGS) approach and in addition single nucleotide polymor-phism (SNP) arrays for the genetic analysis of two independent index patients without familial medical history. Of note, this genetic strategy revealed a homozygous splice site mutation (DSG2–c.378+1G>T) in the first patient and a nonsense mutation (DSG2–p.L772X) in combination with a large deletion in DSG2 in the second one. In conclusion, a recessive inheritance pattern is likely for both cases, which might contribute to the hidden medical history in both families. This is the first report about these novel loss-of-function mutations in DSG2 that have not been previously identi-fied. Therefore, we suggest performing deep genetic analyses using NGS in combination with SNP arrays also for ACM index patients without obvious familial medical history. In the future, this finding might has relevance for the genetic counseling of similar cases.


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