NEW FINDINGS From the FRENCH COHORT of MYH9-RELATED DISORDERS: PHENOTYPE PECULIARITIES and GENOTYPE NOVELTIES on Behalf of the National French Reference Center on Inherited Platelet Disorders (CRPP)

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1155-1155
Author(s):  
Béatrice Saposnik ◽  
Sylvie Binard ◽  
Alan T. Nurden ◽  
Paquita Nurden ◽  
Nicole Schlegel
Keyword(s):  
Splice Site ◽  
Conflicts Of Interest ◽  
Family Members ◽  
Initial Result ◽  
Compound Heterozygous ◽  
Missense Mutations ◽  
Tail Domain ◽  
Giant Platelets ◽  
New Findings ◽  
Platelet Disorders

Abstract Abstract 1155 MYH9-Related Diseases (RD) are inherited platelet disorders combining thrombocytopenia and giant platelets with various associations of leukocyte inclusions, deafness, nephritis and cataracts. Mutations in the MYH9 gene, that encodes the nonmuscle myosin heavy chain IIA (NMMHC-IIA), are the hallmark of these disorders. Our cohort includes a total of 161 subjects (90 women, 71 men): 76 propositi (37 isolated, 39 family index cases) with MYH9 mutations and 85 family members (45 women, 40 men) belonging to the 39 unrelated families. The cases with an identified mutation were classified according to the location of the mutation either in the motor domain (MD patients (P): “MDP”) or in the tail domain (TD patients (P): “TDP”) of NMMHC-IIA. MYH9 mutations were found in a total of 109 subjects: the 76 propositi (45 women, 31 men) and 33/85 (38.8%) family members (19 women, 14 men, from 22 families). Among the 41 different mutations detected, the majority were missense mutations (33 = 80.5%) and new (25 = 61%). Two substitutions in intron 39 were discovered for the first time: 1 in the donor splice site (corresponding to a classical MYH9-RD phenotype) and the other in position minus 3 of the acceptor splice site (moderate thrombocytopenia only without giant platelets). A total of 15 different exons were identified as having mutations, 4 exons remained unaffected. Mutations were more frequently found in exons 1, 16, 26, 30, 38 and 40, as already published. The majority of patients (102 = 93.6%) were heterozygous for one mutation but 7 patients (6.4%) were compound heterozygous for 2 mutations. Significant differences between MDP and TDP were found for bleeding symptoms (65% of MDP, 33% of TDP, p=0.0037), nephropathy (31.5% of MDP, 11.6% of TDP, p=0.015), age (years, mean) at onset for nephropathy (21 for MDP, 48 for TDP, p=0.0003), deafness (54% of MDP, 23.7% of TDP, p=0.0025), and association bleeding/extra-hematological symptoms (68.2% of MDP, 27.7% of TDP, p=0.01). Patients with bleeding had a lower platelet count than non-bleeders (mean= 42G/L versus 62G/L, p=0.0024) but there were no significant differences in the percentage of giant platelets. ITP (splenectomy for 7) was the initial misdiagnosis for 29/69 (42%), (51.7% of MDP, 35% of TDP, p= 0.165). Cataracts occurred in 4 patients only. Altogether these results showed that the clinical phenotype of MYH9-RD was more severe for MDP than TDP. New mutations were discovered and were widespread along the exons and in some cases two mutations were identified in the same patient. The sequencing of the full gene and all exons-introns boundaries should be mandatory for each patient whatever the initial result. Disclosures: No relevant conflicts of interest to declare.

Six Different Point Mutations in Seven Danish Families with Symptomatic Protein C Deficiency

1995 ◽  
Vol 73 (02) ◽  
pp. 186-193 ◽  
Author(s):  
Bent Lind ◽  
Marianne Schwartz ◽  
Sixtus Thorsen
Keyword(s):  
Splice Site ◽  
Protein C ◽  
Family Members ◽  
Point Mutations ◽  
Patient Specific ◽  
Missense Mutations ◽  
Coding Region ◽  
Protein C Deficiency ◽  
Epidermal Growth Factor Domain ◽  
Increased Risk

SummarySix different point mutations of the protein C gene are described in seven Danish families with protein C deficiency associated with an increased risk of venous thromboembolism. All affected family members are heterozygotes for the mutated protein C genotype. One mutation is a G2992→A transition at position +5 in the 5’ splice site of intron D. The other five mutations affect the protein coding region. One is a Cl432→T transition in exon III converting the highly conserved Arg15 to Trp in the Gla-domain. Another mutation is a G3157→C transversion in exon V converting the non-conserved Gly72 to Arg in the epidermal growth factor domain. The remaining three mutations are located in non-conserved amino acid positions in exon IX and affect the serine proteinase domain. The first is a G8559→C transversion converting Gly282 to Arg. The second is a C8571→T transition (present in two families) converting Arg286 to Cys. The third is a C8695→T transition converting Pro327 to Leu. In each family the protein C deficiency cosegregates or probably cosegregates (one family, G8559→C) with the mutation. All affected family members exhibit a reduction of both the antigen and the functional plasma concentration of protein C to approximately 50% of normal indicating that the mutated protein C is not present (type 1 deficiency) or only present in low amounts in plasma. Agarose gel electrophoresis followed by Western blotting shows that the Arg15→Trp substitution is associated with a normal as well as an abnormal migrating plasma protein C band. This provides positive evidence for that both the normal and mutated alleles are expressed (type 2 deficiency). The five other mutations are associated with only one band with the mobility of normal protein C. In one family a novel G1390→A transition converting the normal Ala1 to Thr was demonstrated. This mutation is not linked to the patient specific G8559→C transversion. In conclusion one splice site mutation and five different missense mutations of the protein C gene are described.

scholarly journals Rare Variants in GP1BB underlie Autosomal Dominant Macrothrombocytopenia; Findings of Large Unique Bleeding and Platelet Disorders Cohort

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1359-1359
Author(s):  
Suthesh Sivapalaratnam ◽  
Willem Ouwehand ◽  
Bridge Consortium ◽  
ThromboGenomics Consortium
Keyword(s):  
Conflicts Of Interest ◽  
Thrombus Formation ◽  
Transmembrane Protein ◽  
Medical Center ◽  
Autosomal Recessive Disorder ◽  
Start Codon ◽  
Bleeding Diathesis ◽  
Giant Platelets ◽  
Human Phenotype ◽  
Platelet Disorders

Abstract The incidence of inherited rare bleeding, thrombotic and platelet disorders (BPD) is estimated to be 200-250 per million individuals. For at least 15% of these cases the molecular basis is unresolved (Lentaigne et al, Blood, 2016). We aim to discover the genetic basis of these unresolved BPDs, to improve diagnosis and treatment. In addition this will increase our knowledge of the molecular pathways of megakaryopoiesis, haemostasis and thrombus formation. For this purpose we have established a prospective BPD cohort, which at time of writing consist of 1,378 probands, 123 affected relatives and 41 unaffected relatives. After consenting, all these individuals have been precisely phenotyped using human phenotype ontology (HPO) terms (Westbury et al, Genome Medicine, 2015). This includes clinical parameters, laboratory results and pedigree history. Ten thousand DNA samples from the BPD cases, patients with other rare diseases and their close relatives, who were all enrolled in the NIHR BioResource were analysed by whole genome sequencing (Turro et al, Science Trans. Med, 2016). We applied phenotype similarity regression to identify statistical associations between presence of a coding variants with consequences in a gene and similarity to a latent HPO-coded phenotype (Greene et al, AJHG, 2016). We identified a strong statistical association between presence of 8 unique rare coding DNA variants with consequences in GP1BB and 8 probands with macrothrombocytopenia (SimReg posterior probability = 0.93 with inferred characteristic phenotype preferentially included the term "Increased mean platelet volume", Fisher's p = 2.10 x 10-6). We sought to validate these discovery findings through identification of further cases in the cohorts of 75 and 301 macrothrombocytopenia cases from the ThromboGenomics consortium (Simeoni et al, Blood, 2016) and the Nagoya Medical Center in Japan, respectively. Three additional variants in GP1BB were identified in 9 individuals from 8 pedigrees. Systematic review of the sequencing results of 27 BPD genes (including GP1BA, GP9) implicated in thrombocytopenia in 10 probands did not reveal any alternative variants that could plausibly explaining the phenotype. In aggregate 59 affected macrothrombocytopenia cases were observed in 16 pedigrees with 9 unique GP1BB variants, with the Y113C variant, which was observed in 6 pedigrees thought to be a Japanese founder variant. The means of the count and volume of platelets of the probands was 104.6 x109/l (range 47-172 x109/l) and 12.6 fL, respectively. Inspection of blood smears revealed anisocytosis with a small number of giant platelets and electron micrograph images were reminiscent of those from platelets of a patient with Bernard Soulier syndrome (BSS). In 11 pedigrees measurement by cytometry showed reduced levels of the GpIb/IX/V complex on the platelets of 8 genetically independent individuals and bleeding diathesis was reported in 7 of 16 pedigrees. Altogether, we identified 9 unique variants in the GP1BB gene, which encodes the 202 amino acid long Type 1 transmembrane protein GpIb▢, which together with GpIba, GpV and GpIX form the receptor complex for von Willebrand Factor on megakaryocytes and platelets. They result in a disruption of the canonical methionine start codon, another resulting in a premature stop at residue 46, 5 missense variants at L16P, G43W, T68M, Y113C and L132Q, a deletion removing PAL at residues 79-81, and finally a frameshift in the codon for residue A150 leading to an alternative open reading frame predicted to result in a protein of 193 instead of 202 amino acids long. All 9 variants but the G43W one, which was observed in one of the 61,000 ExAC subjects were unobserved in the ExAC database. In summary before our study there was only one isolated report of a Gp1ba-R42C variant assumed to be causal of macrothrombocytopenia, but no segregation study was performed to corroborate this observation. Our findings in 16 pedigrees with 59 subjects with macrothrombocytopenia provide robust statistical and convincing co-segregation evidence that some variants in GP1BB if present as a single alleleexert a dominant effect on the count and volume of platelets, resulting in some pedigrees in a bleeding diathesis rejecting the dogma that BSS is mainly an autosomal recessive disorder. Disclosures No relevant conflicts of interest to declare.

Genetic Background in Patients with Severe Factor XIII A-Subunit Deficiency Treated with Recombinant FXIII

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1125-1125
Author(s):  
Vytautas Ivaskevicius ◽  
Arijit Biswas ◽  
Anne Thomas ◽  
Ramin Tehranchi ◽  
Johannes Oldenburg
Keyword(s):  
Splice Site ◽  
Factor Xiii ◽  
Splice Site Mutation ◽  
Compound Heterozygous ◽  
Missense Mutations ◽  
Rt Pcr ◽  
Site Mutation ◽  
B Subunit ◽  
A Subunit ◽  
Fxiii Deficiency

Abstract Abstract 1125 Background and Objectives: Congenital Factor XIII (FXIII) deficiency is a rare, autosomal recessive bleeding disorder, with a significant majority of patients showing defects in the FXIII-A subunit. The disease is caused by a variety of F13A1 gene mutations resulting in a severe quantitative FXIII-A type I deficiency. Here, we report a wide spectrum of mutations identified in 41 severe Factor XIII-A deficiency patients (≥6 years of age, mean, 26.4; range, 7–60). Patients and Methods: A total of 41 patients were recruited in a multinational (23 centers, 11 countries), open-label, single-arm, phase 3, prophylaxis trial for the evaluation of the efficacy and safety of a novel recombinant FXIII (rFXIII). Eleven of the 41 patients (Israel [n=8], Switzerland [n=2] and Italy [n=1]) already had established genetic backgrounds and carried previously reported F13A1 mutations. Mutational screening in the remaining 30 patients who had unknown genetic status was done using direct sequencing on an ABI Prism 3130TL (Applied Biosystems, Weiterstadt, Germany). For two patients with splice-site mutations, cDNA analysis was done with RT-PCR (Quiagen One-step RT-PCR kit). The crystallographic model of the recombinant human cellular coagulation FXIIIA zymogen (EC: 2.3.2.13, resolution solved to 2.1Å) was downloaded from the Protein Data Bank (data file 1F13) for viewing, analysis and graphical rendering using YASARAver11.11.2. Classic molecular dynamic simulation approaches were used on the FXIII-A crystal structure to evaluate the effect of the novel missense mutations on protein structure. Results and Discussion: In total, 31 distinct mutations in 41 patients have been identified revealing 13 missense mutations, seven small deletions, six splice-site mutations, three nonsense mutations, one large deletion and one small insertion. Amongst this cohort of mutations, 16 mutations were novel. In one patient, a heterozygous missense mutation was detected in spite of severe deficiency symptoms shown by the patient. We assume that the other mutation could not be detected within the scope of our screening set up. The IVS5–1G>A (c.691–1G>A) splice-site mutation was the most commonly occurring (n=9 [21.9%]) mutation in this cohort. Two siblings carried a missense mutation in F13A1 gene (Ser295Arg) and in combination with a novel variant in F13B gene (Ser634Phe). This variant does not seem to significantly affect the B-subunit stability, since it is located in the terminal part of the molecule. Missense mutations are of special interest since they help to better understand the structure and function of FXIII A-subunit. The MD simulation of four novel missense mutations predicted a damaging effect on the protein structure for three of the missense mutations (Glu229Arg, Leu275Phe, and Arg703Trp) based on changes in bonding patterns, free energy calculations, change in local secondary structure etc. The Leu588Gln located on the surface of barrel 1 domain was not observed to cause a significant change in local structure, nevertheless, owing to its surface presentation it might influence the interaction with FXIII B-subunit. The analysis for the two novel splice-site mutations (IVS7+1G>A, IVS12+1G>A) did not show any aberrant mRNA product. Inhibitor development is the most undesirable side-effect of treatment with plasma-derived or rFXIII products. Overall, the incidence of inhibitors in patients with congenital FXIII deficiency is unknown, but is expected to be much lower compared with other coagulopathies, e.g. hemophilia A. In the present study, none of the patients treated with rFXIII (a mean treatment period of 322 days) developed FXIII neutralizing antibodies. Four patients developed transient low-titer anti-rFXIII antibodies that had no neutralizing activity. Interestingly, two patients (male and female) were siblings carrying the same common splice-site mutation in intron 5 (IVS5-1 G>A). The third patient was compound heterozygous for two missense mutations (Gln229Arg; Ser413Leu). The fourth patient was also found to be compound heterozygous for two missense mutations (Arg77His; Leu275Phe). Conclusion: To conclude, the identified mutations, including 16 novel mutations, are implicated in the causality of severe FXIII deficiency. However, none of these mutations were associated with the development of inhibitory antibodies in the context of treatment with rFXIII. Disclosures: Tehranchi: Novo Nordisk: Employment, Equity Ownership. Oldenburg:Biogen Idec, Swedish Orphan Biovitrum: Honoraria; Baxter, Bayer, Biotest, CSL Behring, Grifols, Inspiration, Novo Nordisk, Octapharma, Pfizer: Honoraria, Research Funding.

scholarly journals Thrombocytopenia Caused By Compound Heterozygous Missense Mutations C.3946G>a in Vwf Gene and C.1825C>T in MYO5A Gene?

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4208-4208
Author(s):  
Rong-Fu Zhou ◽  
Wenjin Gao ◽  
Yueyi Xu
Keyword(s):  
Platelet Count ◽  
Conflicts Of Interest ◽  
Hepatitis Virus ◽  
Cell Metabolism ◽  
Coagulation Factor ◽  
Asian Population ◽  
Compound Heterozygous ◽  
Missense Mutations ◽  
History Of ◽  
Blood Routine

Abstract Objective: One patient with thrombocytopenia from childhood was examined to identify the cause of thrombocytopenia. Methods: The previous medical history of the patient was comprehensively reviewed, with blood routine examination , reticular platelet count, autoantibodies, hepatitis virus full set, thyroid function, plasma coagulation factor VIII activity, vWF activity and antigen testing, and NGS with peripheral blood to detect thrombosis and hemostatic related genes. Results: The female patient, 43 years old, was presented with thrombocytopenia for more than 40 years. She had no history of fever or bleeding with no significant menstrual volume increasing. His father had similar thrombocytopenia but died four years ago. On third June,2021, she had no skin bruises or enlarged spleen. Blood routine test showed wbc 7.4x10 9/l, HB 112g/l, Plt 47x10 9/l and reticular platelet count 1.85%. Hepatitis B surface antibody was 147.08mIU/ml. FVIII:C was 62.0% with vWF:A 17.4% and vWF:Ag 61.9%. NGS results suggested that there was a heterozygous c.3946G> A missense mutations in Exon28 of vWF gene (chr12:6128638) , resulting in p.Val1316Met. The variation is rare in the East Asian population and is shown in the human disease database to cause type 2B vWD, which causes increased platelet clearance due to variation in vWF molecule-platelet binding regions, clinically manifested as mild to moderate platelet reduction. there was also a heterozygous c.1825C>T missense mutation in Exon15 of MYO5A gene (chr15:52676447) , resulting in p.Arg609Cys. There are adverse effects on the structure / function of the MYH12 protein encoded by the MYO5A gene. The MYH12 protein is involved in cell metabolism and cytoskeletal activity, and this protein deficiency might also cause thrombocytopenia, which is clearly warranted to further investigation. Conclusions：compound heterozygous missense mutations c.3946G>A in vWF gene and c.1825C>T in MYO5A gene might caused thrombocytopenia in the patient. Disclosures No relevant conflicts of interest to declare.

Anti-Myelin Oligodendrocyte Glycoprotein Encephalomyelitis and Extensive Longitudinal Transverse Myelitis Associated with Compound Heterozygous NLRP3 Missense Mutations in a Young Child

2020 ◽  
Author(s):  
Deirdre O'Sullivan ◽  
Michael Moore ◽  
Susan Byrne ◽  
Andreas O. Reiff ◽  
Susanna Felsenstein
Keyword(s):  
Young Child ◽  
Genetic Basis ◽  
Transverse Myelitis ◽  
Acute Disseminated Encephalomyelitis ◽  
Myelin Oligodendrocyte Glycoprotein ◽  
Compound Heterozygous ◽  
Missense Mutations ◽  
Childhood Onset

AbstractAcute disseminated encephalomyelitis in association with extensive longitudinal transverse myelitis is reported in a young child with positive anti-myelin oligodendrocyte glycoprotein (MOG) antibody with heterozygous NLRP3 missense mutations; p.(Arg488Lys) and p.(Ser159Ile). This case may well present an exceptional coincidence, but may describe a yet unrecognized feature of the spectrum of childhood onset cryopyrinopathies that contribute to the understanding of the genetic basis for anti-MOG antibody positive encephalomyelitis. Based on this observation, a larger scale study investigating the role of NLRP3 and other inflammasomes in this entity would provide important pathophysiological insights and potentially novel avenues for treatment.

scholarly journals Temporal and mutation-specific alterations in Ca2+ homeostasis differentially determine the progression of cTnT-related cardiomyopathies in murine models

2009 ◽  
Vol 297 (2) ◽  
pp. H614-H626 ◽  
Author(s):  
Pia J. Guinto ◽  
Todd E. Haim ◽  
Candice C. Dowell-Martino ◽  
Nathaniel Sibinga ◽  
Jil C. Tardiff
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Ventricular Myocytes ◽  
Troponin T ◽  
Early Time ◽  
Left Ventricular ◽  
Familial Hypertrophic Cardiomyopathy ◽  
Compensatory Mechanism ◽  
Missense Mutations ◽  
Tail Domain ◽  
Cellular Mechanics

Naturally occurring mutations in cardiac troponin T (cTnT) result in a clinical subset of familial hypertrophic cardiomyopathy. To determine the mechanistic links between thin-filament mutations and cardiovascular phenotypes, we have generated and characterized several transgenic mouse models carrying cTnT mutations. We address two central questions regarding the previously observed changes in myocellular mechanics and Ca2+ homeostasis: 1) are they characteristic of all severe cTnT mutations, and 2) are they primary (early) or secondary (late) components of the myocellular response? Adult left ventricular myocytes were isolated from 2- and 6-mo-old transgenic mice carrying missense mutations at residue 92, flanking the TNT1 NH2-terminal tail domain. Results from R92L and R92W myocytes showed mutation-specific alterations in contraction and relaxation indexes at 2 mo with improvements by 6 mo. Alterations in Ca2+ kinetics remained consistent with mechanical data in which R92L and R92W exhibited severe diastolic impairments at the early time point that improved with increasing age. A normal regulation of Ca2+ kinetics in the context of an altered baseline cTnI phosphorylation suggested a pathogenic mechanism at the myofilament level taking precedence for R92L. The quantitation of Ca2+-handling proteins in R92W mice revealed a synergistic compensatory mechanism involving an increased Ser16 and Thr17 phosphorylation of phospholamban, contributing to the temporal onset of improved cellular mechanics and Ca2+ homeostasis. Therefore, independent cTnT mutations in the TNT1 domain result in primary mutation-specific effects and a differential temporal onset of altered myocellular mechanics, Ca2+ kinetics, and Ca2+ homeostasis, complex mechanisms which may contribute to the clinical variability in cTnT-related familial hypertrophic cardiomyopathy mutations.

scholarly journals Novel compound heterozygous EYS variants may be associated with arRP in a large Chinese pedigree

2020 ◽  
Vol 40 (6) ◽  
Author(s):  
Chunli Wei ◽  
Ting Xiao ◽  
Jingliang Cheng ◽  
Jiewen Fu ◽  
Qi Zhou ◽  
...  
Keyword(s):  
Novel Mutation ◽  
Gene Mutations ◽  
Chinese Family ◽  
Compound Heterozygous ◽  
Missense Mutations ◽  
The Novel ◽  
Pathogenic Variants ◽  
Pathogenic Genes ◽  
Compound Heterozygous Variants ◽  
Normal Controls

Abstract As a genetically heterogeneous ocular dystrophy, gene mutations with autosomal recessive retinitis pigmentosa (arRP) in patients have not been well described. We aimed to detect the disease-causing genes and variants in a Chinese arRP family. In the present study, a large Chinese pedigree consisting of 31 members including a proband and another two patients was recruited; clinical examinations were conducted; next-generation sequencing using a gene panel was used for identifying pathogenic genes, and Sanger sequencing was performed for verification of mutations. Novel compound heterozygous variants c.G2504A (p.C835Y) and c.G6557A (p.G2186E) for the EYS gene were identified, which co-segregated with the clinical RP phenotypes. Sequencing of 100 ethnically matched normal controls didn’t found these mutations in EYS. Therefore, our study identified pathogenic variants in EYS that may cause arRP in this Chinese family. This is the first study to reveal the novel mutation in the EYS gene (c.G2504A, p.C835Y), extending its mutation spectrum. Thus, the EYS c.G2504A (p.C835Y) and c.G6557A (p.G2186E) variants may be the disease-causing missense mutations for RP in this large arRP family. These findings should be helpful for molecular diagnosis, genetic counseling and clinical management of arRP disease.

scholarly journals Non-spherocytic hemolytic anemia caused by erythrocyte pyruvate kinase defiiency: the analysis of genetic defects in pediatric patients, living in Russian Federation

2021 ◽  
Vol 20 (2) ◽  
pp. 84-96
Author(s):  
E. A. Cherniak ◽  
N. E. Sokolova ◽  
K. V. Semiglazova ◽  
I. N. Lavrentyeva ◽  
E. K. Donush ◽  
...  
Keyword(s):  
Medical Research ◽  
Hemolytic Anemia ◽  
Research Center ◽  
Compound Heterozygous ◽  
Missense Mutations ◽  
Pediatric Hematology ◽  
Transfusion Independence ◽  
National Medical ◽  
Retrospective Data Analysis ◽  
Minimum Age

The article presents retrospective data analysis of a cohort of patients with PKD (n = 41 patients, aged 4 months – 26,5 years, median of age – 5 years 1 month) who were examined at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology for unspecifid hereditary hemolytic anemia during the period 2013–2020. The study was approved by the Independent Ethics Committee of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. In all patients, the diagnosis was confimed by Next Generation sequencing (NGS). The homozygous mutations in the PKLR gene were found in 10 patients (24.39%), compound heterozygous mutations in 31 patients (75.61%), 77.78% of them were missense mutations. Gender distribution (male:female) was 1:1.73. At least once transfusion of erythrocyte suspension was required to 40 (97.56%) patients. The minimum age at the time of the debut of transfusion dependence was the fist day of life, the maximum was 4 years. Exchange blood transfusion was performed in 13 children, severe normocytic hyperregenerative anemia with transfusion of red blood cells in the fist days of life was noted in 12 children, at the 1st month of life – in 9 children, at the 2nd month of life – in 8 children, at the 3rd month – in 6 children, at the 5th month – in 2 children, at the 1st year – in 1 child, and 2 children underwent single transfusions on the background of infectious episodes at 3 and 4 years respectively. Splenectomy due to high transfusion dependence was performed in 10 patients: transfusion independence was achieved in 5 patients, in 5 – an increase in the interval between blood transfusions. Median of surgical intervention (9 patients): 7 years 4 months, minimum age – 1 year 4 months, maximum – 14 years 4 months. In total, 36 genotypes were described in 41 patients, among them were: c.1529G>A in 3 patients, c.1137_1139del / c.1456C>T – in 2 patients, c.1079G>A/c.1529G>A in 2 patients, c.1130T>C/c.1456C>T in 2 patients, other genotypes occurred once. Two mutations were the most frequent: c.1456C>T (16.67%) and c.1529G>A (16.67%). 19 (46,34%) of patients had previously not described mutations.

scholarly journals Double heterozygosity for mutations in the platelet glycoprotein IX gene in three siblings with Bernard-Soulier syndrome

Blood ◽  
1993 ◽  
Vol 81 (9) ◽  
pp. 2339-2347 ◽  
Author(s):  
SD Wright ◽  
K Michaelides ◽  
DJ Johnson ◽  
NC West ◽  
EG Tuddenham
Keyword(s):  
Normal Subjects ◽  
Immunoblot Analysis ◽  
Platelet Glycoprotein ◽  
Bleeding Tendency ◽  
Missense Mutations ◽  
Coding Region ◽  
Giant Platelets ◽  
Double Heterozygosity ◽  
Induced Aggregation ◽  
Bernard Soulier Syndrome

Abstract Bernard-Soulier syndrome (BSS) giant platelets have defective and/or deficient glycoprotein (GP) Ib/IX complexes, causing absent ristocetin- induced aggregation, defective interaction with von Willebrand factor, morphologic abnormality, and a clinical bleeding tendency. Recently several mutations have been described in the platelet GPIb alpha gene in individuals exhibiting the BSS phenotype. We have studied a family with classical BSS, and have excluded lesions at the GPIb alpha locus by restriction fragment length polymorphism linkage analysis. Analysis of the genes for two other components of the platelet GPIb:IX complex, namely GPIb beta and GPIX, showed two different missense mutations in the coding region of the GPIX gene: an A-->G transition in codon 21 results in conversion of an aspartic acid to glycine and an A-->G change in codon 45 converts an asparagine residue to serine. Three affected individuals are doubly heterozygous for these mutations, which alter conserved residues in or flanking the GPIX leucine-rich glycoprotein motif. Both mutations create new recognition sites for the enzyme Fnu 4H1; therefore, this enzyme was used to screen 60 normal subjects (120 alleles). Neither mutation was detected in any subject other than direct relatives of the affected individuals. Although low levels of GPIb were demonstrable by both flow cytometry and immunoblot analysis in an affected individual's platelets, there was no evidence of GPIX immunoreactivity. We propose that expression of abnormal GPIX prevents stable assembly of the GPIb/IX complex, causing BSS in the doubly heterozygous individuals in this family.

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