The Canadian "National Program for hemophilia mutation testing" database: a ten-year review.

A reference genotyping laboratory was established in 2000 at Queen's University, Kingston, to provide genetic testing for Hemophilia A (HA) and B (HB) and create a Canadian mutation database. Canadian hemophilia treatment centers and genetics clinics provided DNA and clinical information from November 2000 to March 2011. The factor VIII (F8) gene was analyzed in 1,177 patients (47% of HA population) and 787 female family members and the factor IX (F9) gene in 267 patients (47% of HB population) and 123 female family members, using Southern Blot, PCR, conformation sensitive gel electrophoresis, and/or direct sequencing.

The genetics of Canadian type 3 von Willebrand disease: further evidence for co-dominant inheritance of mutant alleles.

Background: Type 3 von Willebrand disease (VWD) is the most severe form of the disease and is classically inherited in an autosomal recessive fashion.

Objectives: The aim of the current study was to investigate the molecular pathogenesis of a Canadian cohort of type 3 VWD patients.

Patients And Methods: Thirty-four families comprised of 100 individuals were investigated.

Temporal and spatial variations in microclimate influence the larval foraging behaviors and performance of a conifer-feeding sawfly.

Herbivorous insects are often exposed to broad temporal and spatial variations in microclimate conditions within their host plants and have adapted a variety of behaviors, such as avoidance or basking, to either offset or benefit from such variation. Field experiments were carried out to investigate the influence of daily and intratree variations in microclimate on the behaviors (feeding, resting, dispersal, and hiding) and associated performance of late-instar larvae of the yellowheaded spruce sawfly, Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae) within crowns of 1.25-1.

Frequency of platelet type versus type 2B von Willebrand disease. An international registry-based study.

Less than 50 patients are reported with platelet type von Willebrand disease (PT-VWD) worldwide. Several reports have discussed the diagnostic challenge of this disease versus the closely similar disorder type 2B VWD. However, no systematic study has evaluated this dilemma globally.

[Application studies on the gene diagnosis and carrier detection of hemophilia A by using polymerase chain reaction-conformation sensitive gel electrophoresis].

Objective: To establish a simple, rapid and easy method for screening the gene mutation in hemophilia A, which was further applied to a direct diagnosis and carrier detection at gene level.

Methods: Twenty-four clinically diagnosed hemophilia pedigrees, including all the hemophilia patients and female members, were tested for the introns 22 and 1 in factor VIII gene by using inversion polymerase chain reaction (PCR) and regular PCR techniques. All the 26 exons of factor VIII gene were consecutively screened in the 17 patients manifesting non-inverted sequences in intron 22 by using PCR, subsequently all the 37 amplicons resulted from 26 exons were analyzed by conformation sensitive gel electrophoresis (CSGE), finally the mutated exons were subjected to sequencing verification.

Different clinical phenotype in triplets with haemophilia A.

Although many patients with haemophilia may have exactly the same residual clotting factor level, the clinical disease phenotype may vary greatly. This variation may be related to different genetic mutations responsible for haemophilia, environmental influences and co-inheritance of polymorphisms affecting the coagulation system. The study of siblings with haemophilia offers the opportunity to examine additional factors, other than genetic mutation and environment that may impact on the clinical phenotype of haemophilia.

The mutational spectrum of type 1 von Willebrand disease: Results from a Canadian cohort study.

In order to evaluate the changes within the VWF gene that might contribute to the pathogenesis of type 1 von Willebrand disease (VWD), a large multicenter Canadian study was undertaken. We present data from the sequence analysis of the VWF gene in 123 type 1 VWD index cases and their families. We have identified putative mutations within the VWF gene in 63% (n = 78) of index cases, leaving 37% (n = 45) with no identified changes.

DNA microarray analysis for the detection of mutations in hemophilia A.

Background: Congenital deficiency of factor (F) VIII results in the inherited X-linked bleeding disorder hemophilia A. More than 900 different mutations are reported in the hemophilia A mutation database with the largest number of mutations being single nucleotide substitutions distributed throughout the gene. Complicating the molecular characterization of this disease is the complexity of the F8 gene, the mutational heterogeneity, and technical limitations of the current mutation detection techniques.

Genetic linkage and association analysis in type 1 von Willebrand disease: results from the Canadian type 1 VWD study.

Background: von Willebrand disease (VWD) is the most common bleeding disorder known in humans, with type 1 VWD representing the majority of cases. Unlike the other variant forms of VWD, type 1 disease represents a complex genetic trait, influenced by both genetic and environmental factors.

Aim: To evaluate the contribution of the von Willebrand factor (VWF) and ABO blood group loci to the type 1 VWD phenotype, and to assess the potential for locus heterogeneity in this condition, we have performed genetic linkage and association studies on a large, unselected type 1 VWD population.

Aminoglycoside suppression of nonsense mutations in severe hemophilia.

Aminoglycoside antibiotics exhibit their bactericidal effect by interfering with normal ribosomal activity. In this pilot study, we have evaluated the effect of the aminoglycoside antibiotic gentamicin on the factor VIII (FVIII) and IX levels of severe hemophiliacs with known nonsense mutations. Five patients were enrolled and each patient was given 3 consecutive days of gentamicin at a dose of 7 mg/kg intravenously every 24 hours.

Intensive exposure to factor VIII is a risk factor for inhibitor development in mild hemophilia A.

Background: Inhibitors are rare in boys with mild hemophilia A (MHA; factor (F)VIII:C > 5%) but may arise following intense FVIII exposure, e.g. continuous infusion (CI).

Distribution of FMR1 and FMR2 alleles in Javanese individuals with developmental disability and confirmation of a specific AGG-interruption pattern in Asian populations.

The number of trinucleotide repeats in the 5' untranslated regions of the FMR1 and FMR2 genes was determined by PCR in 254 Fragile XA-negative Javanese male children with developmental disabilities. The distribution of FMR1 and FMR2 trinucleotide repeat alleles was found to be significantly different in the Indonesian population with developmental disability compared to that in developmentally disabled populations in North America and Europe (p & 0.021).

Genetic diversity at the FMR1 locus in the Indonesian population.

We report an analysis of allelic diversity at short tandem repeat polymorphisms within the fragile XA locus in 1069 male volunteers from twelve Indonesian sub-populations. An odd numbered allele of DXS548 was found at high frequency in all Indonesian populations. Greater allelic diversity was identified at the loci under study than has been previously reported for an Asian population.

Patients with features similar to Huntington's disease, without CAG expansion in huntingtin.

Objective: To describe characteristics of gene-negative patients with clinical features of Huntington's disease (HD), exploring likely etiologies.

Background: When a direct gene test became definitive for diagnosis of HD, we discovered a number of patients in our clinics in Baltimore, MD, and Cambridge, UK, believed or suspected to have HD who did not have the triplet repeat expansion.

Methods: Patients were examined using standardized instruments, and given full neurologic and psychiatric evaluations.

Analysis of spinocerebellar ataxia types 1, 2, 3, and 6, dentatorubral-pallidoluysian atrophy, and Friedreich's ataxia genes in spinocerebellar ataxia patients in the UK.

Accurate clinical diagnosis of the spinocerebellar ataxias (SCAs) can be difficult because of overlap in phenotype with other disorders and variation in clinical manifestations. Six SCA loci have been mapped and four disease causing genes identified, in addition to the causative gene for Friedreich's ataxia (FA). All of the identified mutations are expansions of trinucleotide repeat tracts.

Homozygotes and heterozygotes for ciliary neurotrophic factor null alleles do not show earlier onset of Huntington's disease.

The CAG repeat number on Huntington's disease (HD) chromosomes accounts for about 60% of the variance in the age at onset of HD. However, distinct familial factors may also influence the age at onset. HD is associated with loss of medium-sized GABA-ergic striatal output neurons.

Dentatorubral and pallidoluysian atrophy (DRPLA). Clinical and neuropathological findings in genetically confirmed North American and European pedigrees.

Dentatorubral and pallidoluysian atrophy (DRPLA) is an autosomal dominant disorder that clinically overlaps with Huntington's disease (HD) and manifests combinations of chorea, myoclonus, seizures, ataxia, and dementia. DRPLA is caused by a CAG triplet repeat (CTG-B37) expansion coding for polyglutamine on chromosome 12 and exhibits the genetic phenomenon of anticipation. This neurodegenerative disease has only rarely been reported in non-Japanese pedigrees, and there are only a few neuropathological studies in genetically confirmed patients.

Analysis of the 5' upstream sequence of the Huntington's disease (HD) gene shows six new rare alleles which are unrelated to the age at onset of HD.

The CAG repeat number in the Huntington's disease (HD) gene accounts for about 50% of the variation seen in age at onset of HD. In order to determine whether promoter sequence variation can contribute to the residual variation in age at onset, we studied the conserved 303 bp region upstream of the +1 translation start site in the HD gene in a population of 56 control East Anglians, 30 Africans, 34 Japanese, and 208 English Huntington's disease patients. A surprisingly high degree of variation was found.

Genotypes at the GluR6 kainate receptor locus are associated with variation in the age of onset of Huntington disease.

Huntington disease (HD) is associated with abnormal expansions of a CAG repeat close to the 5' end of the IT15 gene. We have assembled a set of 293 HD subjects whose ages of onset were known and sized their HD CAG repeats. These repeats accounted for 69% of the variance of age of onset when we used the most parsimonious model, which relates the logarithm of age of onset to a function of CAG repeat number.

Non-Mendelian transmission at the Machado-Joseph disease locus in normal females: preferential transmission of alleles with smaller CAG repeats.

Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3, is a neurodegenerative disorder which is associated with a CAG repeat expansion in the MJD1 gene on chromosome 14q32.1. A recent study reported an excess of transmission of disease chromosomes relative to normal chromosomes from affected fathers, while this phenomenon was not observed in female meioses.

Analysis of polyglutamine-coding repeats in the TATA-binding protein in different human populations and in patients with schizophrenia and bipolar affective disorder.

A new class of disease (including Huntington disease, Kennedy disease, and spinocerebellar ataxias types 1 and 3) results from abnormal expansions of CAG trinucleotides in the coding regions of genes. In all of these diseases the CAG repeats are thought to be translated into polyglutamine tracts. There is accumulating evidence arguing for CAG trinucleotide expansions as one of the causative disease mutations in schizophrenia and bipolar affective disorder.