A novel mutation in a Turkish patient with Hermansky-Pudlak syndrome type 5

The Hermansky-Pudlak syndrome (HPS) is a rare genetically heterogeneous autosomal recessive disorder, characterized by tyrosinase-positive oculocutaneous albinism, platelet dysfunction and lysosomal ceroid lipofuscin storage. This is caused by defects in lysosome-related organelles. In humans eight different types of the syndrome are known, of which a short overview is given. The clinical features and a novel mutation of a patient with HPS type 5 are described here.     

Marked bleeding diathesis in patients with platelet dysfunction due to a novel mutation in RASGRP2, encoding CalDAG-GEFI (p.Gly305Asp)

Congenital platelet function disorders are often the result of defects in critical signal transduction pathways required for platelet adhesion and clot formation. Mutations affecting RASGRP2, the gene encoding the Rap GTPase activator, CalDAG-GEFI, give rise to a novel, and rare, group of platelet signal transduction abnormalities. We here report platelet function studies for two brothers (P1 and P2) expressing a novel variant of RASGRP2, CalDAG-GEFI(p.Gly305Asp). P1 and P2 have a lifelong history of bleeding with severe epistaxis successfully treated with platelet transfusions or rFVIIa. Other bleedings include extended hemorrhage from minor wounds. Platelet counts and plasma coagulation were normal, as was αIIbβ3 and GPIb expression on the platelet surface. Aggregation of patients’ platelets was significantly impaired in response to select agonists including ADP, epinephrine, collagen, and calcium ionophore A23187. Integrin αIIbβ3 activation and granule release were also impaired. CalDAG-GEFI protein expression was markedly reduced but not absent. Homology modeling places the Gly305Asp substitution at the GEF-Rap1 interface, suggesting that the mutant protein has very limited catalytic activity. In summary, we here describe a novel mutation in RASGRP2 that affects both expression and function of CalDAG-GEFI and that causes impaired platelet adhesive function and significant bleeding in humans.     

The immune thrombocytopenic purpura (ITP) bleeding score: assessment of bleeding in patients with ITP

A method for objective quantification of bleeding symptoms in immune thrombocytopenic purpura (ITP) has not been established. The ITP Bleeding Scale (IBLS) is a novel bleeding assessment system comprising 11 site-specific grades. Implementation of the IBLS on 100 patient visits revealed that although platelet count and large platelet count correlated well with bleeding symptoms overall, this relationship disappeared in marked thrombocytopenia. The IBLS is a useful clinical tool for monitoring bleeding and may be used to aid the development of laboratory parameters that correlate with underlying bleeding propensity in thrombocytopenia.     

Coinheritance of Factor V (FV) Leiden enhances thrombin formation and is associated with a mild bleeding phenotype in patients homozygous for the FVII 9726+5G>A (FVII Lazio) mutation

We investigated the role of thrombophilic mutations as possible modifiers of the clinical phenotype in severe factor VII (FVII) deficiency. Among 7 patients homozygous for a cross-reacting material-negative (CRM-) FVII defect (9726+5G>A, FVII Lazio), the only asymptomatic individual carried FV Leiden. Differential modulation of FVII levels by intragenic polymorphisms was excluded by a FVII to factor X (FX) gene haplotype analysis. The coagulation efficiency in the FV Leiden carrier and a noncarrier was evaluated by measuring FXa, FVa, and thrombin generation after extrinsic activation of plasma in the absence and presence of activated protein C (APC). In both patients coagulation factor activation was much slower and resulted in significantly lower amounts of FXa and thrombin than in a normal control. However, more FXa and thrombin were formed in the plasma of the patient carrying FV Leiden than in the noncarrier, especially in the presence of APC. These results were confirmed in FV-FVII doubly deficient plasma reconstituted with purified normal FV or FV Leiden. The difference in thrombin generation between plasmas reconstituted with normal FV or FV Leiden gradually decreased at increasing FVII concentration. We conclude that coinheritance of FV Leiden increases thrombin formation and can improve the clinical phenotype in patients with severe FVII deficiency.     

Brugada综合征患者SCN5A基因突变检测

目的对体检中发现的两例无症状的Brugada综合征患者进行SCN5A基因突变检测。方法收集两个家系所有成员的外周血样标本,提取基因组DNA后应用聚合酶链式反应（PCR）扩增心脏电压门控钠通道蛋白α亚单位基因SCN5A的所有编码区序列,并直接进行DNA序列测定,若有碱基变异,则与200个正常样本进行对照,并分析相应的氨基酸改变。结果在一个患者的一条染色单体上发现SCN5A基因碱基变异:即第1712位密码子的第1个碱基的G→T改变,导致相应编码的甘氨酸（G）被半胱氨酸（C）所取代,而这一基因变异在200个正常人的对照中均未发现。家系调查发现患者的一个妹妹也具有相同的基因变异,但心电图无明显异常。结论在一个体检发现的Brugada综合征患者的SCN5A基因上发现一个未报道过的碱基变异,该碱基变异可能是新的基因突变位点。     

Brugada syndrome with a novel missense mutation in SCN5A gene: A case report from Bangladesh

Brugada syndrome is an inherited cardiac arrhythmia that follows autosomal dominant transmission and can cause sudden death. We report a case of Brugada syndrome in a 55-year-old male patient presented with recurrent palpitation, atypical chest pain and presyncope. ECG changes were consistent with type 1 Brugada. Gene analysis revealed a novel missense mutation in SCN5A gene with a genetic variation of D785N and a nucleotide change at 2353G-A. One of his children also had the same mutation. To our knowledge this is the first genetically proved case of Brugada syndrome in Bangladesh.     

Intracerebral hemorrhage in a patient with SLE and catastrophic antiphospholipid syndrome (CAPS): report of a case

A 31-year-old woman was admitted to the hospital for investigation of left lower limb thrombophlebitis. History, physical examination, and laboratory investigations led to the diagnosis of systemic lupus erythematosus (SLE), complicated by secondary antiphospholipid syndrome (APS). Treatment included steroids, azathioprine, aspirin, and low molecular weight heparin. Sixty-three days later, she was admitted to the hospital again because of high fever, macroscopic hematuria, and dyspnea. Laboratory testing showed anemia and impaired renal function. High-resolution chest computed tomography (CT) revealed bilateral multiple peribronchial infiltrates with hemorrhage. Magnetic resonance imaging (MRI) angiography of the kidneys revealed left renal vein thrombosis combined with ischemia of the left kidney. Cyclophosphamide and methylprednisolone pulse treatment as well as intravenous immunoglobulins were started immediately. Despite intensive immunosuppressive and supportive treatment, she suffered three relapses of alveolar hemorrhage and died on day 40, due to severe intracerebral bleeding. The final diagnosis was catastrophic APS with diffuse alveolar hemorrhage and kidney involvement. The unusual combination of recurrent alveolar hemorrhage and death from intracerebral hemorrhage rather than thrombosis in a CAPS patient is discussed.     

A novel missense mutation in the human plasmin inhibitor (alpha2-antiplasmin) gene associated with a bleeding tendency

Heterozygosity for a G --> A mutation converting Val384(GTG) to Met(ATG) associated with plasmin inhibitor (alpha2-antiplasmin) deficiency was identified in three family members with bleeding tendency. The proband had traumatic breast haematoma and per-/postoperative bleeds. An affected daughter required a blood transfusion after a normal delivery and a son had prolonged bleeding after tooth extraction. The plasma plasmin inhibitor activities of the affected family members were reduced to 49-66% of normal. The antigenic concentrations determined by electroimmunoassay were reduced to 57-68% of normal. Crossed immunoelectrophoresis of plasma from the proband showed a normal pattern. The amino acid Val384 is located eight residues C-terminal (P8') of the P1 residue (Arg376) in the reactive site. The P8' residues of bovine and mouse plasmin inhibitor are both Val. Among other serpins the P8' residue is unconserved. The mutation was not present in the non-affected family member or 30 blood donors. In addition to the Val384Met mutation two new polymorphisms Ala-26(GCG)/Val(GTG) and Arg407(AGG)/Lys(AAG) and one previously reported polymorphism Arg6(CGG)/Trp(TGG) were identified in the plasmin inhibitor gene of the family. The allelic frequencies among 30 blood donors with normal values of plasma plasmin inhibitor (functional) were 0.84/0.16 for C/T in codon -26, 0.81/0.19 for C/T in codon 6 and 0.83/0.17 for G/A in codon 407.     

Identification of a new Bruton’s tyrosine kinase (BTK) mutation associated with a mild phenotype in a child with X‐linked agammaglobulinemia (XLA)

Summary This study reports a new X‐linked agammaglobulinemia (XLA) mutation and its phenotypic features in a 6½‐year‐old boy. Different clinically defined subtypes of XLA may exist according to different genetic alterations and to other defect signalling molecules or pathways of B cell maturation.     

Next generation sequencing in bleeding disorders: two novel variants in the F5 gene (Valencia-1 and Valencia-2) associated with mild factor V deficiency

Journal of Thrombosis and Thrombolysis - Inherited bleeding coagulation disorders (IBCDs) have a powerful diagnostic tool in next generation sequencing (NGS) that not only offers confirmation of...     

Analyses of a novel SCN5A mutation (C1850S): conduction vs. repolarization disorder hypotheses in the Brugada syndrome

AIMS: Brugada syndrome (BrS) is characterized by arrhythmias leading to sudden cardiac death. BrS is caused, in part, by mutations in the SCN5A gene, which encodes the sodium channel alpha-subunit Na(v)1.5. Here, we aimed to characterize the biophysical properties and consequences of a novel BrS SCN5A mutation. METHODS AND RESULTS: SCN5A was screened for mutations in a male patient with type-1 BrS pattern ECG. Wild-type (WT) and mutant Na(v)1.5 channels were expressed in HEK293 cells. Sodium currents (I(Na)) were analysed using the whole-cell patch-clamp technique at 37 degrees C. The electrophysiological effects of the mutation were simulated using the Luo-Rudy model, into which the transient outward current (I(to)) was incorporated. A new mutation (C1850S) was identified in the Na(v)1.5 C-terminal domain. In HEK293 cells, mutant I(Na) density was decreased by 62% at -20 mV. Inactivation of mutant I(Na) was accelerated in a voltage-dependent manner and the steady-state inactivation curve was shifted by 11.6 mV towards negative potentials. No change was observed regarding activation characteristics. Altogether, these biophysical alterations decreased the availability of I(Na). In the simulations, the I(to) density necessary to precipitate repolarization differed minimally between the two genotypes. In contrast, the mutation greatly affected conduction across a structural heterogeneity and precipitated conduction block. CONCLUSION: Our data confirm that mutations of the C-terminal domain of Na(v)1.5 alter the inactivation of the channel and support the notion that conduction alterations may play a significant role in the pathogenesis of BrS.     

A novel mutation in the G4.5 (TAZ) gene in a Greek patient with Barth syndrome

Barth Syndrome (BTHS) is a rare X-linked recessive inborn error of metabolism, which is characterized by dilated cardiomyopathy, neutropenia, skeletal myopathy and short stature. Barth Syndrome is associated with mutations in the tafazzin (TAZ) gene at Xq28 that result in cardiolipin deficiency and abnormal mitochondria. Here we report a 5.5-month old boy with BTHS phenotype who carries a novel missense T43P mutation in exon 2 of the TAZ gene.     

A novel DO null allele with a c.268C>T (p.Gln90Stop) mutation in Japanese

The Dombrock blood group system consists of two antithetical antigens, Do^a (DO1) and Do^b (DO2), and seven high‐prevalence antigens, Gy^a (DO3), Hy (DO4), Jo^a (DO5), DOYA (DO6), DOMR (DO7), DOLG (DO8) and DOLC (DO9). Do^a/Do^b polymorphism is associated with c.793A>G (p.Asn265Asp) in exon 2 of the DO (ART4) gene, and the corresponding alleles are named DO*01 and DO*02. The rare Do_null or Gy(a?) phenotype lacks all Dombrock antigens, and the DO null alleles vary with both DO*01 and DO*02 backgrounds. We report a novel DO null allele, which has a c.268C>T (p.Gln90Stop) nonsense mutation with a DO*02 background identified from four unrelated Gy(a?) Japanese individuals.     

Bohring-Opitz syndrome caused by a novel ASXL1 mutation (c.3762delT) in an IVF baby: A case report

Rationale:Bohring-Opitz syndrome is a severe congenital disorder associated with a de novo mutation in the additional sex combs-like 1 (ASXL1) gene, and it is characterized by symptoms that include developmental delay and musculoskeletal and neurological features.Patient concerns:The patient was a girl, an in vitro fertilization (IVF) baby, with delayed motor development, drooling, short stature, slow growth, low muscle tone, image diagnosis of hypoplasia of the corpus callosum, delayed tooth eruption, high palatal arch, adduction of the thumb, drooling, not chewing, excessive joint activity, and ligament relaxation.Diagnosis:Whole-exome sequencing analysis detected 1 novel disruptive frameshift mutation in ASXL1 in the proband but wild-type ASXL1 in both parents.Interventions:Approximately 1 year of rehabilitation training, which included exercise therapy, toy imitation operation, cognition of daily objects, daily living skills training, gesture language training, oral muscle training, and hand movement training.Outcomes:After approximately 1 year of training, the patient was 3 years old and able to eat normally without drooling. She was able to grasp objects and pick them up after they fell. She was able to grasp small objects and actively played with toys. In addition, she was able to crawl on the floor (at slow speed, with poor initiative), stand with assistance, and walk with assistance; she was unstable when standing unassisted (standing unassisted for 8 seconds at most during training).Lesson:ASXL1 c.3762delT is a novel mutation that may be caused by IVF. This finding suggests that appropriate gene mutation detection approaches may be necessary for IVF technology.     

Identification of a novel point mutation (Leu72Pro) in the NADH-cytochrome b5 reductase gene of a patient with hereditary methaemoglobinaemia type I

Utilizing polymerase chain reaction (PCR) related technology, we investigated the b5R gene of a Chinese patient with hereditary methaemoglobinaemia type I and found a novel missense mutation (CTC-CCC) at codon 72 in exon 3 of the gene. As the mutation generates an Apa I recognition site, homozygosity for the mutation was confirmed by restriction analysis of PCR-amplified fragments from the patient's genomic DNA. We predicted that the residue replacement of Leu with Pro of the mutant enzyme would account for the b5R deficiency in the patient. The results further confirm the genetic polymorphism of b5R gene mutations found in the RCM type I.     

A 1063G-->A mutation in exon 12 of glycoprotein (GP)IIb associated with a thrombasthenic phenotype: mutation analysis of [324E]GPIIb

We report the molecular, genetic and functional analysis of a case of thrombasthenic phenotype. The proband showed absence of platelet glycoprotein (GP)IIb and very low content of GPIIIa, and both his parents showed a marked reduction in the levels of platelet GPIIb-IIIa. Single-stranded conformational polymorphism-polymerase chain reaction (SSCP-PCR) analysis and direct sequencing of PCR-amplified GPIIb exon-12 revealed the presence of a G-->A transition at position 1063 with the expected substitution of glutamate 324 with lysine (K). This mutation did not alter the level of GPIIb mRNA. Co-expression of normal or mutant [324K] GPIIb with normal human GPIIIa in Chinese hamster ovary (CHO) cells failed to show surface exposure of [324K]GPIIb-IIIa complexes. Pulse-chase and immunoprecipitation analysis demonstrated that [324K]GPIIb cDNA was translated into proGPIIb, but neither mutant GPIIb heavy chain (GPIIbH) nor [324K]GPIIb-GPIIIa complexes were detected, suggesting that this mutation is the underlying molecular basis for the thrombasthenic phenotype. Mutation analysis demonstrated that 324E of GPIIb could be replaced by other negatively charged or polar amino acids (AAs) without impairing the surface expression of GPIIb-IIIa. However, substitution of 324E of GPIIb for a positively charged AA other than K prevented the expression of GPIIb-IIIa complexes. These observations suggest that a domain encompassing 324E of GPIIb is essential for heterodimerization with GPIIIa and its substitution for a positively charged residue precludes normal subunit association.     

Prevalence,burden and treatment effects of vaginal bleeding in women with (suspected) congenital platelet disorders throughout life: a cross-sectional study

Congenital platelet disorders (CPDs) are rare bleeding disorders that are associated with mucocutaneous bleeds. However, data on vaginal bleeding in women with CPDs are scarce. A set of generic and bleeding-specific questionnaires were used to evaluate the prevalence of vaginal bleeding, its impact on quality of life (QoL) and sexual functioning and the consequences for pregnancy, miscarriage and delivery in a cohort of women who were referred for diagnostic evaluation for CPDs. A total of 78 women included in the study were either diagnosed with a CPD (n = 35) or were clinically suspected of a CPD (n = 43). Heavy menstrual bleeding (HMB) was reported by a large proportion of women, which mainly started at menarche. In all, 76% of women received any kind of HMB treatment, often leading to surgical prodecures. HMB was shown to have a high impact on QoL, which improved upon treatment. Even though women reported that vaginal bleeding affects sexuality, this topic is not frequently discussed with physicians. Heavy blood loss frequently occurred after miscarriage/delivery, often requiring treatment. Women with (suspected) CPDs frequently encounter HMB, negatively impacting daily life and sexual functioning. Together with peripartum bleeding, these data highlight the burden of vaginal bleeding in CPDs and importance of adequate treatment.