Biomedical subjects

P Beighton

Publications and source records attributed to P Beighton.

At least 145 records · Page 8Linked to original sources

PubMed1985

Retinitis pigmentosa in South Africa.

Retinitis pigmentosa (RP), the commonest inherited form of blindness, is a heterogeneous condition which usually manifests as an isolated abnormality, but is occasionally a component of various rare syndromes. The basic defect in RP is unknown, but the recent molecular genetic discovery of linkage with a restriction fragment length polymorphism in X-linked RP offers the potential for carrier screening and antenatal diagnosis of this form of the disorder. In this article we present an overview of RP and an analysis of our findings from a questionnaire survey of 130 affected individuals in 63 families in the Cape Province and Natal. The proportions of the different genetic types of RP were generally in accordance with those found in overseas studies, being 14% autosomal dominant, 9,5% autosomal recessive and 6% X-linked recessive. A further 35% of the affected persons had RP together with other syndromic stigmata, while the remaining 35% could not be classified into any specific genetic category.

Female↗

PubMed1985

Ectrodactyly in central Africa.

Autosomal dominant ectrodactyly has been identified in several families in remote areas of central Africa. Two groups from eastern Botswana and south-western Zimbabwe belong to the Talaunda tribe and have a common ancestral origin. Another family are members of the Wadoma tribe of north-eastern Zimbabwe. A total of 24 individuals may be affected. Tenuous historical evidence suggests that the Talaunda migrated from the eastern Zambezi region late in the last century and may have the same origins as the Wadoma tribe. On this basis it is likely that the affected people have the same faulty gene, which presumably arose by mutation in a common progenitor.

Adolescent↗

PubMed1985

Genetic disorders on the island of St Helena.

The island of St Helena lies in the South Atlantic ocean and is isolated by distance from any land mass and by lack of a harbour or airfield. In these circumstances there could be an unusual pattern of inherited disease, and for this reason we have attempted to document the presence and frequency of genetic conditions in the population, which numbers approximately 5 500. Genetic disorders identified included autosomal dominant genu valgum, hereditary angioneurotic oedema, Christmas disease and pseudo-achondroplasia. The presence of the autosomal recessive form of retinitis pigmentosa provides a possible explanation for the occurrence of that condition in the islanders of Tristan da Cunha, since they have ancestral links with the St Helena community. The recognition of these genetic disorders in this isolated population has practical implications in terms of clinical management and the provision of medical services.

Achondroplasia↗

PubMed1985

Detection of a high frequency RsaI polymorphism in the human pro alpha 2(I) collagen gene which is linked to an autosomal dominant form of osteogenesis imperfecta.

Screening of the pro alpha 2(I) collagen genes of Southern African populations for restriction fragment length polymorphisms (RFLPs) has revealed a locus polymorphic for the restriction enzyme RsaI. The frequency of the RFLP was 0.38 in Afrikaners, but much lower in indigenous Southern African populations, which suggests that it is of European origin. The polymorphism was used to study 19 affected and non-affected individuals in a four generation family with the autosomal dominant disorder, osteogenesis imperfecta (OI) type I. Co-inheritance of the loss of the RsaI site and the OI phenotype was observed with a lod score of 3.91 at a recombination fraction (theta) of zero, indicating strong linkage. This suggests that the defect in this family is caused by a structural mutation within or close to the pro alpha 2(I) collagen gene. The use of this high frequency RFLP together with other recently described polymorphisms at this locus will facilitate the analysis of the role of this gene in OI and other inherited disorders of connective tissue.

Black People↗

PubMed1985

Linkage studies of X-linked mental retardation: high frequency of recombination in the telomeric region of the human X chromosome (fragile site/linkage/recombination/X chromosome).

One of the commonest forms of X-linked mental retardation is associated with a fragile site at Xq27 on the human X chromosome which can be visualised structurally after culturing cells in folate-deficient media. Unusually, the mutation can be transmitted through a phenotypically normal male. There is already some evidence that the gene loci for G6PD and factor IX are linked to this mental retardation locus. We have followed the inheritance of a DNA sequence 52A, in fragile site families that are also informative for factor IX. We demonstrate that these probes are localised at Xq27/Xq28-Xqter, close physically to the fragile site. We did not find close linkage between 52A, factor IX, and the fragile site in the families studied despite 52A and factor IX showing linkage in normal families. We discuss the importance of these data for the genetic mapping of this region of the human X chromosome and the implication for the use of these DNA probes for clinical diagnosis.

Animals↗

PubMed1985

X-linked Ehlers-Danlos syndrome type V; the next generation.

Two English families with the X-linked form (Type V) of the Ehlers-Danlos syndrome (EDS) who were investigated almost 20 years ago have been re-studied. In one family, the potentially heterozygous sister of 3 affected brothers had born two sons, of whom one has EDS. The 3 brothers had all procreated, producing a total of 2 sons and 3 daughters, all of whom are clinically normal. These pedigree data provide further evidence to support the syndromic identity and X-linked mode of inheritance of this form of the EDS. In the second family, two affected brothers had both procreated; one had produced three normal offspring, while the other had a son with soft extensible skin and a daughter with articular hypermobility. The syndromic status of this kindred is uncertain. Serum copper and ceruloplasmin concentrations in affected males and obligate carrier females in both families were normal. Cytogenetic investigations, including high resolution banding, yielded normal results.

Adolescent↗

PubMed1985

The ocular form of osteogenesis imperfecta: a new autosomal recessive syndrome.

We have investigated a South African family of Indian stock in which 4 brothers and 2 cousins had a severe form of osteogenesis imperfecta (OI) together with blindness due to hyperplasia of the vitreous, corneal opacity and secondary glaucoma. To the best of our knowledge the syndromic association of OI and ocular problems of this type has not previously been reported, and we believe that this condition is a newly recognised entity. The pedigree is consistent with autosomal recessive inheritance.

Blindness↗

PubMed1985

On the paradoxically high relative prevalence of osteogenesis imperfecta type III in the black population of South Africa.

In a survey of Black patients with osteogenesis imperfecta (OI) attending the Baragwanath Hospital, Johannesburg, the severe autosomal recessive OI type III was recognized in 21, of whom 18 lived in the Johannesburg area. By contrast only 5 had the ostensibly common mild autosomal dominant OI type I. The estimated minimum population frequency is 0.6 per hundred thousand for OI type III in this group and 0.1 per hundred thousand for OI type I. These figures are the reverse of those calculated for White Australians, where the ratio between OI type I and III is of the order of 7 to 1. This anomalous situation has important genetic and practical implications.

Adult↗

PubMed1985

Obstetric aspects of Gaucher disease.

The medical aspects of 21 pregnancies in 11 women with type I, non-neuronopathic Gaucher disease have been reviewed. One pregnancy ended in a spontaneous abortion at 12 weeks and two pregnancies in one patient resulted in two children with the Hurler syndrome which is unrelated to Gaucher disease. The other 18 pregnancies resulted in the birth of normal infants at full-term, four by caesarean section and the remainder by normal vaginal delivery. Only one patient experienced a significant exacerbation of her Gaucher disease during pregnancy. Fifteen of the pregnancies were associated with mild haematological complications but active intervention was necessary in only two instances. It can be concluded that there are few contraindications to pregnancy in women with Gaucher disease.

Abortion, Spontaneous↗

PubMed1985

Ophthalmological complications in the sclerosing bone dysplasias.

The sclerosing bone dysplasias are a group of rare genetic disorders in which overgrowth of the cranio-facial skeleton causes a variety of ophthalmological complications. During the past decade more than 100 South Africans with conditions in this category have been investigated and their ocular manifestations have been appraised. Sclerosteosis was diagnosed in 45 persons. In 70% of the affected adults progressive thickening of the skull led to elevation of intracranial pressure and papilloedema. Proptosis and divergent strabismus was present in 25%, while excessive lacrimation due to bone obstruction of the tear ducts was seen in 28%. Evidence of compression of cranial nerves was present in the majority of patients, but visual loss due to involvement of the second cranial nerve did not occur. Three related patients with the severe autosomal recessive form of oculodento-osseous dysplasia had visual impairment with microphthalmia, microcornea and cataracts, which had been present since birth. The severe autosomal recessive form of osteopetrosis was encountered in two infants, both of whom developed optic atrophy and became blind. The benign autosomal dominant form of osteopetrosis was diagnosed in ten persons; none had ocular involvement. Other sclerosing bone dysplasia patients with ocular involvement included two males with frontometaphyseal dysplasia and gross supra-orbital enlargement and five children with pycnodysostosis and scleral blueing.

Adult↗

PubMed1984

A clinical and ultrastructural study of osteogenesis imperfecta after flavonoid (Catergen) therapy.

A trial of the flavonoid Catergen (Zyma) has been undertaken in 11 adults with osteogenesis imperfecta (Ol). The only significant clinical or metabolic side-effects were severe headaches, which necessitated the withdrawal of 3 patients from the trial. Patient compliance in terms of palatability of Catergen was good, and 3 of the 8 patients who completed the trial experienced subjective improvement. After 6 months' treatment with Catergen, the abnormally narrow collagen fibrils found in the osteoid region in a pretreatment bone biopsy specimen from a middle-aged man with the common type 1 (autosomal dominant) form of Ol showed a significant reversion to normal diameters. Post-treatment specimens from his 2 affected sons, who exhibited the same defect, showed a similar but less marked response.

Adult↗

PubMed1984

Pseudoxanthoma elasticum in South Africa--genetic and clinical implications.

After investigation by a multidisciplinary team, 19 cases of biopsy-proven pseudoxanthoma elasticum are described. Evidence for an increased gene frequency in the Afrikaner population was found, as was support for the claim of genetic heterogeneity in the disorder. The well-described clinical manifestations involving the eyes, skin and cardiovascular system were seen, as were more rarely reported features such as acne, telangiectasia of the lips and bilateral cataracts. Mitral valve prolapse and gastro-intestinal haemorrhage were not found in our patients, although there are several reports in the literature.

Adolescent↗

PubMed1984

South African human genes in health and disease--a molecular genetics approach.

Recombinant DNA technology is playing an increasingly important role in diagnostic confirmation, carrier detection and the prenatal diagnosis of inherited disorders. This article summarizes current progress in the application of this technology to clinically important genetic conditions in South Africa and outlines its potential role in the future practice of medical genetics in this country.

Anemia, Sickle Cell↗

PubMed1984

Glucose-6-phosphate dehydrogenase deficiency in the Greek population of Cape Town.

A sample of 250 unrelated members of the Greek community of Cape Town was studied in order to establish the prevalence of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency in the community. A gene frequency of 0,067 in males and a prevalence of 6,7% are estimated for this group. It is recommended that persons with G-6-PD deficiency should have access to a list of medicinal agents which have the potential for precipitating acute haemolytic crises and that they should wear Medic-Alert discs bearing information concerning the disorder.

Female↗

PubMed1984

A computerized genetic record system.

The quantity of data stored in manual medical records--which is a function of the level of sophistication of medical practice--has become unmanageable. The need for efficient access to this information can be met by computerization. A number of automated medical record systems have been developed for this purpose, invariably by physicians with computer expertise. The recent development of 'application generators' (a specific group of versatile packaged software systems) now enables a wide range of applications to be effectively computerized by end-users (the people who ultimately use the systems) who have no knowledge of computers. The utilization of an application generator to computerize the medical records of patients seen at the Department of Human Genetics of the University of Cape Town Medical School is described and discussed.

Computers↗

PubMed1984

Namaqualand hip dysplasia: an autosomal dominant entity.

A unique inherited skeletal disorder has been identified in 45 persons in five generations of a kindred of mixed ancestry in South Africa. Discomfort in the hip joints develops in childhood and the course is progressive, with handicap in middle age. General health is good, height is not reduced by any significant degree, and there is no nonskeletal involvement. The major changes are in the femoral capital epiphyses, which are flattened and fragmented; secondary degenerative arthropathy develops at a later stage. Platyspondyly of variable but mild degree is present in about 60% of affected persons. Other minor changes, including iliac exostoses, are present occasionally. Pedigree data indicate autosomal dominant inheritance, with a reasonably consistent phenotypic expression. In view of the geographic distribution of this condition we propose the designation "Namaqualand hip dysplasia" (NHD).

Adult↗

PubMed1984

The split-hand and split-foot anomaly in a central African Negro population.

The split-hand and split-foot anomaly (ectrodactyly) was identified in five individuals of three generations of a kindred from a remote African Village; seven more were known to be affected in a further two generations. The malformations were confined to the hands and feet and inherited as an autosomal dominant trait with variable expression. Bilateral triphalangeal thumbs were present in three of the affected individuals.

Abnormalities, Multiple↗

PubMed1984

X-linked inheritance of ocular albinism with late-onset sensorineural deafness.

We have investigated a large Afrikaner kindred in which seven males had ocular albinism and late-onset sensorineural deafness (OASD). The pattern of inheritance of OASD is X-linked recessive. To the best of our knowledge, this association has not previously been reported and in order to establish syndromic identity we describe and discuss the condition in this article.

Adult↗