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Biomedical subjects

N C Nevin

Publications and source records attributed to N C Nevin.

At least 127 records · Page 7Linked to original sources
PubMed1990

DNA analysis and recombination in X-linked retinitis pigmentosa.

X-linked retinitis pigmentosa is a hereditary retinal degenerative disorder which has been localised to the proximal short arm of the X chromosome. Recent evidence suggests that the disorder is heterogeneous with two possible loci for the disease mutation. DNA analysis on the family presented in this paper showed that the mutation mapped to the more telomeric locus (RP3), thus enabling two flanking polymorphic DNA probes (XJ1.1 and M27 beta) to be used for the detection of female carriers in the family. In none of the carriers was a tapetal reflex (metallic sheen) observed.

Adult↗
PubMed1990

Carrier estimations in Duchenne muscular dystrophy families in Northern Ireland using RFLP analysis.

Intragenic RFLP analysis was used to provide carrier risk estimations on 100 possible female carriers from 22 Duchenne muscular dystrophy families. This enabled 78% of possible carriers to be assigned high or low risks (greater than 90% or less than 10%) as opposed to 26% assigned low risk on pedigree data alone. When a single polymorphism is not informative the use of haplotype analysis for carrier estimations is illustrated for one family.

Computers↗
PubMed1990

Linkage data for Marfan syndrome and markers on chromosomes 1 and 11.

Six large families with classical Marfan syndrome were studied using markers on chromosomes 1 and 11. Two of three families tested showed negative scores using D1S7 but a third family gave a positive score (0.92) at theta = 0.1. The other chromosome 1 markers typed (MUCI, NGFB, D1S8) excluded close linkage. Negative lod scores with two chromosome 11q22 markers (D11S84, D11S148) excluded at least 20 cM in this area (Z = less than -2), which was chosen for study as two enzymes responsible for collagen degradation (collagenase and stromelysin) are localised to this region.

Chromosomes, Human, Pair 1↗
PubMed1990

Pontobulbar palsy and neurosensory deafness (Brown-Vialetto-Van Laere syndrome) with possible autosomal dominant inheritance.

A female with the Brown-Vialetto-Van Laere syndrome is described. The patient's father, a paternal uncle, and possibly a paternal first cousin had neurosensory deafness and a paternal aunt had clinical symptoms indicative of the syndrome. This family raises the possibility that the disorder is genetically heterogeneous with autosomal recessive and autosomal dominant forms. Alternatively, it could be caused by a mutant gene on the X chromosome.

Adolescent↗
PubMed1989

Orofaciodigital syndrome type IV: report of a patient.

We describe a further patient with the orofaciodigital syndrome type IV. The clinical characteristics include lobulated tongue, pseudo-cleft of lip, pre- and postaxial polydactyly of hands and feet, severe talipes equinovarus, mesomelic limb shortness associated with tibial hypoplasia, and severe bilateral deafness. Five similar cases including the present patient are now on record. Autosomal recessive inheritance is likely.

Abnormalities, Multiple↗
PubMed1989

Cytogenetic investigations in a family with ataxia telangiectasia.

Cytogenetic findings on a family with ataxia telangiectasia (A-T) in which three of four sibs were affected are described. The affected individuals had approximately twice the level of spontaneous chromosome breakage of a normal control, while the parents and the normal sib had no significant increase. Lymphocytes from all three A-T homozygotes showed specific stable chromosomal rearrangements involving chromosomes 7 and 14. All of these abnormalities involved breakage at the usual four sites associated with A-T (7p14, 7q35, 14q12, and 14q32). Two rearrangements detected in the eldest and most severely affected patient were clones, one of which [t(14;14)(p11;q12)] is not commonly found in A-T cells. No chromosomal rearrangements were encountered in lymphocytes from the control, the parents, or the normal sib. Lymphocytes from the A-T patients also were found to be 7-11 times more sensitive to the induction of chromatid aberrations by X-irradiation than control cells. Lymphocytes from the parents and normal sib showed a moderately increased frequency of X-ray induced aberrations compared with that of the control.

Ataxia Telangiectasia↗
PubMed1989

Linkage disequilibrium and CF allele segregation analysis in cystic fibrosis families in Northern Ireland.

Linkage disequilibrium and cystic fibrosis (CF) allele segregation were analysed in 46 CF families in Northern Ireland. The smaller (+) allele of the KM19/PstI polymorphism and the larger (-) allele of the XV-2c/TaqI polymorphism showed marked linkage disequilibrium with CF. This information can be used to alter the risk of an individual being a carrier of CF away from the expected population risk of 1 in 20. The high-risk genotypes K+K+ or X-X- have a risk of 1 in 10 and the low-risk genotypes K-K- or X+X+ have a risk of 1 in 50. A study of the segregation of CF alleles in the 46 families, using KM19 and Xv-2c, showed preferential inheritance of the paternal (79%), as opposed to the maternal (21%), CF allele by the heterozygous carriers. A mechanism that might explain this observation is discussed.

Alleles↗
PubMed1989

Congenital anomalies in twins in Northern Ireland. I: Anomalies in general and specific anomalies other than neural tube defects and of the cardiovascular system, 1974-1979.

Data are presented from a large-scale population-based study in Northern Ireland, in which multiple sources of ascertainment were used. As found in other studies, the overall prevalence at birth of congenital anomalies amongst twins (285.4/10,000) was somewhat higher than the rate amongst singletons (241.8/10,000). Unlike in other studies, however, the rate amongst twins of like sex (287.8/10,000) was not markedly higher than that amongst twins of unlike sex (252.3/10,000). Problems of comparison between series are discussed.

Diseases in Twins↗
PubMed1989

Congenital anomalies in twins in Northern Ireland. II: Neural tube defects, 1974-1979.

In a large population-based study in Northern Ireland during the period 1974-1979, the rate of anencephalus in twins (9.1/10,000) was found to be less than that in singletons (24.3/10,000). This finding is in contrast with most other studies and the possibility of underascertainment of twin cases is considered, but it is concluded that chance is the likeliest explanation. The rate of spina bifida in twins (36.4/10,000) was similar to that in singletons (31.9/10,000). All of the twins with anencephalus were female and from pairs of like sex. Rates of spina bifida in twins from pairs of the two sex types were similar but, unusually, there was a male preponderance. As in previous studies, the great majority of twins with NTDs had unaffected cotwins.

Anencephaly↗
PubMed1989

Congenital anomalies in twins in Northern Ireland. III: Anomalies of the cardiovascular system, 1974-1978.

Rates of congenital anomalies of the cardiovascular system were compared between twins and singletons in a population-based study in Northern Ireland during the period 1974-1978. Multiple sources of ascertainment were used. As in previous studies, the rate of anomalies of the cardiovascular system in twins (91.0/10,000) was higher than the rate in singletons (66.4/10,000). The excess was confined to twins from pairs of like sex and, in the main, anomalies of the circulatory system other than of the heart itself were involved. Problems in the interpretation of this excess are discussed. No twins were concordant for congenital cardiovascular anomalies of any type.

Diseases in Twins↗
PubMed1989

Neural tube defect recurrence after 'partial' vitamin supplementation.

A total of 227 mothers enrolled for periconceptional multivitamin supplementation because of previous neural tube defect (NTD) births took vitamins for less than the recommended minimum period (at least 28 days before conception until two menstrual periods have been missed). Of 213 examined infants/fetuses born to these partially supplemented mothers, two had NTD, one of whom followed four previous NTDs. The observed NTD recurrence rate is similar to that observed in fully supplemented mothers. A further 14 mothers started supplements before the second missed period but after the normal time of neural tube closure. Three of their offspring had NTD. The significance of this apparently high recurrence rate is discussed.

Ascorbic Acid↗
PubMed1989

T cell receptor beta chain polymorphisms are associated with cystic fibrosis.

The BglII polymorphism near the constant region of the T cell receptor beta chain (TCR c beta) has been investigated in normal controls, patients with cystic fibrosis (CF), and CF carriers. A significant increase was found in the frequency of the 10.0:9.2 kb heterozygous genotype in the CF carrier group (71%) as compared with normal controls (44%) (p = 0.005). Patients with CF also showed an increased frequency of the heterozygous genotype but this was not significant. These results represent a previously unreported disease association and suggest that there may be some form of epistatic interaction between the CF gene and the TCR beta genes such that the double heterozygote is immunologically advantaged.

Cystic Fibrosis↗