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Biomedical subjects

E Giblett

Publications and source records attributed to E Giblett.

10 recordsLinked to original sources

Linkage disequilibrium of plasminogen polymorphisms and assignment of the gene to human chromosome 6q26-6q27.

Linkage disequilibrium was observed between newly identified DNA polymorphisms and a previously described protein polymorphism for plasminogen. This finding implies that the two types of polymorphisms describe variation at the same locus. The plasminogen gene was mapped to chromosomal bands 6q26-q27 using somatic-cell hybrids and in situ hybridization. Linkage disequilibrium between protein and DNA polymorphisms has utility in substituting for protein typing in instances where only DNA samples are available, such as from deceased individuals or extinct species. The technique may be useful when cross-hybridizing sequences make the interpretation of Southern blot patterns difficult and may obviate the need for extensive DNA sequencing. In some cases, disequilibrium may provide information useful for determining the appropriate direction for chromosome walks from a marker locus to a target locus.

Alleles↗

Human C4 haplotypes with duplicated C4A or C4B.

In the course of study of families for the sixth chromosome markers HLA-A, C, B, D/DR, BF, and C2, the two loci for C4, C4A, and C4B, and glyoxalase I, we encountered five examples of probable duplication of one or the other of the two loci for C4. In one of these, both parents and one sib expressed two different structural genes for C4B, one sib expressed one, and one sib expressed none, suggesting that two C4B alleles were carried on a single haplotype: HLA-A2, B7, DR3, BFS1, C2C, C4A2, C4B1, C4B2, GLO1. In a second case, two siblings inherited C4B*1 and C4B*2 from one parent and C4B*Q0 from the other. This duplication appeared on the chromosome as HLA-AW33, B14, DR1, BFS, C2C, C4A2, C4B1, C4B2, GLO2. In a third, very large family with 3 generations, a duplication of the C4B locus occurred which was followed in 2 generations. In one individual, there were three C4B alleles and two C4A alleles. One of the C4B alleles had a hemolytically active product with electrophoretic mobility near C4B2 and was designated C4B*22. It segregated with C4B1 in the family studied. The complete haplotype was HLA-A11, CW1, BW56, DR5, BFS, C2C, C4A3, C4B22, C4B1, GLO2. In another family with 12 siblings, one parent and eight children expressed two C4A alleles on the haplotype HLA-AW30, BW38, DR1, BFF, C2C, C4A3, C4A2, C4BQ0, GLO1.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome Mapping↗

Partial trisomy 20 confirmed by gene dosage studies.

We describe a female infant with multiple congenital anomalies and mental retardation, pre- and postnatal growth failure, microcephaly, unusual facial appearance, and minor skeletal anomalies, all very suggestive of the partial trisomy 20(p) syndrome. Although she was born to karyotypically normal parents, she had an extra small metacentric chromosome. Analysis of metaphase and prometaphase chromosomes by GTG banding and Giemsa 11 staining showed that the extra chromosome was a number 20 with a deletion of the distal end of the long arm. Gene dose studies of adenosine deaminase (ADA) and inosine triphosphatase (ITP) supported the cytogenetic interpretation.

Abnormalities, Multiple↗

Haemoglobin M Hyde Park occurring as a fresh mutation: diagnostic, structural, and genetic considerations.

Hb M Hyde Park disease was detected in a girl who for several years was thought to have cyanotic heart disease. The problems of recognizing the condition are outlined and clues to diagnosis are discussed. Evidence for heme loss from the aberrant beta chains of Hb M Hyde Park and production of an unstable molecule is presented. The normal haematological findings in the patient's parents, as well as their blood groups and isozymes, suggest that the occurrence of her Hb M Hyde Park was the result of a fresh mutation.

Blood Group Antigens↗

The occurrence of gonadal dysgenesis in association with monozygotic twinning.

A case is presented of a monozygotic twin pair, discordant for phenotypic sex, in which the female member showed gonadal dysgenesis and chromosomal mosaicism. Review of the pertinent literature reveals that in monozygotic twin pairs, phenotypic and karyotypic concordance is the usual occurrence for Down's and Klinefelter's syndromes, whereas discordance often accompanies gonadal dysgenesis. Mosaicism is a frequent concomitant of gonadal dysgenesis in monozygotic twins. Our case strengthens the probability of a real association between mosaicism and monozygotic twinning in gonadal dysgenesis.

Adolescent↗