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D S Millar

Publications and source records attributed to D S Millar.

50 records · Page 3Linked to original sources
PubMed1991

The molecular genetics of haemophilia A: screening for point mutations in the factor VIII gene using the restriction enzyme TaqI.

A combination of Southern blotting and the analysis of polymerase chain reaction (PCR) amplified DNA fragments was used to screen the factor VIII genes of 527 haemophilia A patients for point mutations within TaqI restriction sites. Since this "directed search" strategy yielded only four gene lesions, it was concluded that its efficacy is less than that originally predicted. One novel point mutation was however found in a moderately severe haemophiliac; a CGA (Arg) to CTA (Leu) transversion at codon 2209, an evolutionarily conserved residue in the C2 domain of the factor VIII protein. The remaining three detected lesions, CGA (Arg)----TGA (Term) transitions at codons 2116, 2147 and 2307, respectively, have been reported before and are consistent with recurrent mutation at these hypermutable sites. A number of TaqI restriction site polymorphisms/rare variants were also noted. These variants appear to be population-specific but are nevertheless potentially useful in individual cases as intragenic markers for carrier detection and antenatal diagnosis.

Base Sequence↗
PubMed1991

Carrier detection in haemophilia A by direct analysis of factor VIII gene lesions.

CGA----TGA (Arg----Term) transitions in the factor VIII gene causing severe haemophilia A were detected in two patients at codons 336 and 427 using a combination of oligonucleotide discrimination hybridization and DNA sequencing. Carrier detection analysis was then performed by polymerase chain reaction/direct sequencing of the appropriate region of the gene in female relatives of the probands.

Base Sequence↗
PubMed1990

The molecular genetic analysis of hemophilia A: a directed search strategy for the detection of point mutations in the human factor VIII gene.

A directed-search strategy for point mutations in the factor VIII gene causing hemophilia A was used to screen eight potentially hypermutable CpG dinucleotides occurring at sites deemed to be of functional importance. Polymerase chain reaction-amplified DNA samples from 793 unrelated individuals with hemophilia A were screened by discriminant oligonucleotide hybridization. Point mutations were identified in 16 patients that were consistent with a model of 5-methylcytosine (5mC) deamination. Four new examples of recurrent mutation were demonstrated at the following codons: 336 (CGA----TGA), 372 (CGC----TGC), 372 (CGC----CAC), and 1689 (CGC----TGC). These are functionally important cleavage sites for either activated protein C or thrombin. Further novel C----T transitions were identified in the remaining arginine codons screened (-5, 427, 583, 795, and 1696), resulting in the creation of TGA termination codons. Differences in mutation frequency were found both within and between the CpG sites and between ethnic groups. These differences are assumed to be due to differences in the level of cytosine methylation at these sites, although direct evidence for this inference is lacking.

Base Sequence↗
PubMed1990

Detection of a novel point mutation causing haemophilia A by PCR/direct sequencing of ectopically-transcribed factor VIII mRNA.

Specifically-primed reverse transcripts of lymphocyte-derived factor VIII (FVIII) mRNA were successfully amplified by means of the polymerase chain reaction (PCR) thus further extending the phenomenon of ectopic ("illegitimate") transcription of tissue-specific genes. The diagnostic potential of a basal rate of transcription in non-expressing tissues was then demonstrated by the detection of a novel point mutation in the FVIII gene causing haemophilia A by PCR/direct sequencing of ectopically transcribed mRNA derived from patient lymphocytes.

Base Sequence↗
PubMed1990

The molecular genetic analysis of haemophilia A; characterization of six partial deletions in the factor VIII gene.

In a survey of 528 unrelated haemophilia A patients, six partial deletions of the factor VIII (FVIII) gene were detected by Southern blotting. These deletions were further mapped by a combination of Southern blotting and polymerase chain reaction amplification and found to vary in length between 4.7 kb and 57 kb. The frequency of detectable FVIII gene deletions (about 1%) frequency of detectable FVIII gene deletions (about 1%) is thus considerably lower than previously reported. Statistical analysis of currently available data did not provide any evidence for a deletion "'hotspot". Four of the six deletion patients reported here possessed inhibitors. Taken together with previous data, deletion of the FVIII gene was found to be associated with an approximately five-fold higher risk of developing inhibitors compared with other severe haemophiliacs without gene deletions.

Blotting, Southern↗
PubMed1990

Improved carrier detection of haemophilia A using novel RFLPs at the DXS115 (767) locus.

Two novel restriction fragment length polymorphisms (RFLPs) around the DXS115 (767) locus, detectable with the restriction enzymes MspI, are described. Since DXS115 is closely linked to the factor VIII gene (F8C), the MspI RFLP was employed in haemophilia A carrier detection. The utility of these RFLPs lies in the increased applicability and accuracy of diagnoses carried out in cases where available intragenic markers are uninformative.

Deoxyribonuclease HpaII↗
PubMed1985

Fetal haematology in rhesus isoimmunisation.

Haematological studies were carried out in pure fetal blood samples obtained fetoscopically in 29 rhesus isoimmunised pregnancies at 18-24 weeks' gestation, and the values were compared with those obtained in 62 normal control pregnancies. Fetal reticulocytosis or erythroblastaemia was seen only in association with a haemoglobin concentration of 4 g/dl or less. Ten of the 14 fetuses with a haemoglobin concentration below 4 g/dl showed ultrasonographic evidence of hydrops.

Erythroblasts↗
PubMedDate not supplied

Normal blood cell values in the early mid-trimester fetus.

Samples of pure fetal blood from 116 fetuses of 15-21 weeks' gestation were obtained by direct vision fetoscopy. Ninety nine of these fetuses, presumed to be haematologically normal, were suitable for analysis. The data obtained show that the erythropoietic system is evolving rapidly in this gestational age range. The myeloid series shows no significant increase or decrease in numbers apart from eosinophils and basophils which increase significantly with gestational age whereas the platelet count remains constant. The growing application of fetoscopic blood sampling to the prenatal diagnosis and management of fetal blood disorders renders mandatory a knowledge of normal fetal blood values.

Erythrocyte Count↗