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Biomedical subjects

A P Read

Publications and source records attributed to A P Read.

At least 91 records · Page 5Linked to original sources
PubMed1987

Bridging markers defining the map position of X linked hypophosphataemic rickets.

Hypophosphataemic rickets is commonly an X linked dominant hereditary disorder associated with a renal tubular defect in phosphate transport and bone deformities. The gene causing this disorder has been mapped to Xp22.31----p21.3 by using cloned human X chromosome sequences identifying restriction fragment length polymorphisms (RFLPs) in linkage studies of affected families. The hypophosphataemic rickets gene locus (HPDR) was previously mapped distal to the X linked polymorphic locus DXS41 (99.6) but its position in relation to the distal loci DXS43 (D2) and DXS85 (782) was not established. In order to obtain a precise mapping of the disease locus in relation to these genetic loci, additional affected families informative for these X linked markers have been investigated. The combined results from the two studies have established linkage with the loci DXS41 (99.6) and DXS43 (D2); peak lod score for DXS41 (99.6) = 7.35, theta = 0.09, and peak lod score for DXS43 (D2) = 4.77, theta = 0.16. Multilocus linkage analysis mapped the hypophosphataemic rickets gene distal to the DXS41 (99.6) locus and proximal to the DXS43 (D2) locus, thereby revealing two bridging genetic markers for the disease.

Chromosome Mapping↗
PubMed1987

Wolf-Hirschhorn locus is distal to D4S10 on short arm of chromosome 4.

We report a family in which Wolf-Hirschhorn syndrome in two children with partial monosomy of the short arm of chromosome 4 is the result of unbalanced segregation of a reciprocal 4;12 translocation in the mother. Studies with the DNA probe G8 show that the translocation breakpoint in this family is distal to the D4S10 locus. Previously reported cases of Wolf-Hirschhorn syndrome have involved the deletion of D4S10. These observations may prove helpful in the search for better genetic markers for Huntington's chorea, which maps close to D4S10.

Abnormalities, Multiple↗
PubMed1986

Mapping of human X-linked hypophosphataemic rickets by multilocus linkage analysis.

Eleven families with X-linked dominant hypophosphataemic rickets (HPDR) have been typed for a series of X chromosome markers. Linkage with probe 99.6 (DXS41) was demonstrated with a peak lod score of 4.82 at 10% recombination. Multilocus linkage analysis showed that HPDR maps distal to 99.6; this probe has previously been located at Xp22.31-p21.3 by in situ hybridisation. In the mouse hypophosphataemia (Hyp) maps to the distal part of the X chromosome; our location in man is consistent with a scheme which relates the mouse and human X chromosomes by two rearrangements. No marker has yet been found which shows no recombination with HPDR.

Animals↗
PubMed1986

Recurrent neural tube defects, risk factors and vitamins.

Data from our trial of periconceptional vitamin supplementation for the prevention of neural tube defects have been analysed to assess the influence of various factors on recurrence rates of neural tube defect. Our data suggest that the risk of recurrence of neural tube defect is influenced by the number of previous neural tube defects, area of residence, immediately prior miscarriage, and interpregnancy interval. None of these factors, however, contributed any significant differential risk between supplemented and unsupplemented mothers. Hence we conclude that the highly significant difference in recurrence rates of neural tube defect between supplemented and unsupplemented mothers was due to vitamin supplementation.

Abortion, Spontaneous↗
PubMed1986

A register based system for gene tracking in Duchenne muscular dystrophy.

A total of 102 families with Duchenne muscular dystrophy has been studied with linked DNA polymorphisms as an aid to estimating carrier risks for female relatives. Early work using probes RC8, L1.28, and pXUT23 gave very little clinically useful information because of the high recombination rates between these probes and Duchenne muscular dystrophy and the low proportion of women who were heterozygous. Clinically useful results were obtained using probes 99-6, 754, and particularly pERT87. Examples are given of deductions which can be made using these probes. The importance of a genetic register is stressed as a tool for long term contact with the families and other professionals.

Female↗
PubMed1986

Genetic analysis in rheumatoid arthritis.

The use of heritability studies, haplotype sharing, and lod score analysis are reviewed. Twin and family studies show that any genes conferring susceptibility to rheumatoid arthritis must have a relatively low penetrance. This is a serious obstacle to linkage analysis in families. Where there is a population association, as with DR4, studies of haplotype sharing by affected sibs may yield more information if the observations are compared with the sharing predicted from the population association.

Arthritis, Rheumatoid↗
PubMed1984

Consanguinity and complex cardiac anomalies with situs ambiguus.

A survey of British born Asian and English populations of children with congenital cardiac anomalies showed an increased incidence in the Muslim Asian population of complex lesions with visceral heterotaxia. There is a very high incidence of parental consanguinity among Muslim Asian children with complex congenital cardiac anomalies that is even higher than in the general Muslim Asian population of the area studied. The evidence suggests an important recessive genetic component in complex cardiac lesions with visceral heterotaxia, but segregation analysis does not support pure recessive inheritance.

Abnormalities, Multiple↗
PubMed1983

Further experience of vitamin supplementation for prevention of neural tube defect recurrences.

In accordance with a previous protocol, a second cohort of 254 mothers with a history of previous neural tube defect (NTD) births was before a subsequent conception and continued until the time of the second missed menstrual period. There were 2 NTD recurrences (0.9% of 234 infants/fetuses examined), which is significantly fewer than the 11 NTD recurrences (5.1% of 215 infants/fetuses examined) born to 219 unsupplemented (US) mothers in the same centres over the same period. When the data for the two cohorts were combined, the overall recurrence rates were 0.7% for 454 fully supplemented (FS) mothers and 4.7% for 519 US mothers. The recurrence rates after 1 previous NTD were 0.5% for FS and 4.2% for US mothers: after 2 or more previous NTDs, 2.3% for FS and 9.6% for US. There were no recurrences among the offspring of a further 114 mothers whose duration of supplementation fell short of the full regimen (partially supplemented, PS).

Female↗
PubMed1982

Amniotic fluid acetylcholinesterase: a retrospective and prospective study of the qualitative method.

After retrospective evaluation with stored samples, the qualitative acetylcholinesterase (AChE) test has been used prospectively in conjunction with alpha-fetoprotein (AFP) assay on 986 amniotic fluid specimens received in this laboratory during 1980. The main value of AChE is in classifying fluids in which the AFP level is near the threshold between normal and abnormal. Among abnormal pregnancies with raised AFP levels, neural-tube defects can generally be distinguished from other abnormalities by careful appraisal of the AChE gel pattern, but confirmation of these other fetal abnormalities may require high resolution diagnostic ultrasonography and perhaps fetoscopy. Neural-tube defects with false negative AFP levels can be detected by AChE, but AChE gives occasional false positives so that it cannot be relied on in isolation for the diagnosis of neural-tube defects.

Acetylcholinesterase↗