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Biomedical subjects

S Holloway

Publications and source records attributed to S Holloway.

At least 73 records · Page 4Linked to original sources
PubMed1986

Probably Norrie's disease due to mutation. Two sporadic sibships of two males each, a necropsy of one case, and, given Norrie's disease, a calculation of the gene mutation frequency.

Two sibships, each with two affected males but no other affected family members, are described. All four patients at birth had small eyes with white masses visible behind clear lenses. Support for a diagnosis of Norrie's disease lies in the probable mental retardation and sudden death of one child and mental retardation in the other in one of the families, and strong support in the sensorineural deafness in one child in the other family. A necropsy was performed on the dead child. Both eyes showed the retinae to be totally non-attached. The optic nerves were thin. If the diagnosis is Norrie's disease (highly probable), the birth of the second affected child in each family supports the postulate of a mutation in the X chromosome of a germ cell of a maternal grandparent or an earlier maternal ancestor, no previous member of the family having been affected. That implies a 50% risk of the disease in future male siblings and a 50% risk of the carrier state in female sibs. When only one child is affected, the explanation could also be a mutation in that individual. Given Norrie's disease, we have calculated a mutation rate of 3.9 per million chromosomes in the Scottish population--remarkably similar to the mutation rates calculated for many dominant diseases. A diagnosis of autosomal recessive non-attachment of retina implies a 25% risk to later siblings.

Blindness↗
PubMed1979

Prospective study of genetic counselling.

A prospective study was carried out on 200 consecutive subjects seen for counselling (consultands) for serious genetic disorders. Educational and social background of consultands and their knowledge and understanding of their particular problem were assessed before counselling, and their response was determined immediately afterwards and three months and two years later by an independent observer not concerned in the genetic counselling. The husband's educational background was particularly important in influencing a couple's comprehension of counselling. X-linked recessive and chromosomal disorders presented the most difficulties in comprehension. The counsellors' assessment of comprehension was a good guide to the consultands' comprehension as assessed at subsequent follow-up. The proportion deterred from having children increased with time and over a third had been sterilised within two years of counselling. It is suggested that follow-up after counselling should be routine, especially when the counsellor suspects that comprehension has not been good, in X-linked recessive and chromosomal disorders, and when the risks of having an affected child are considered to be high.

Adult↗
PubMed1979

A study of possible heterogeneity in Duchenne muscular dystrophy.

One possible explanation for the apparently high birth incidence of Duchenne muscular dystrophy (DMD), a lethal X-linked disorder, is genetic heterogeneity. As a first step in possibly demonstrating genetic heterogeneity, affected boys were sub-divided into those with and without severe mental handicap. In those with severe mental handicap, ages at onset and of becoming confined to a wheelchair were later, the fall in SCK level with age was less marked, and the urinary excretion of certain aminoacids was greater than in affected boys with normal intelligence. Though the number of subjects investigated was relatively small (15 in each group) and further studies are therefore needed, the results suggest that DMD may not be a single disease entity.

Adolescent↗
PubMed1977

Some considerations in planning organizational change.

Three major types of organizational change are identified (alterations in behavior, technology, and structure), and the respective impact of each is explored. The difficulties in assessing the significance of a change idea are noted, and some criteria are suggested by which such an assessment can be made (e.g., the number of organizational elements affected by the change). The paper concludes by noting practice implications stemming from an understanding of the types of change and their significance for those participants who have limited formal power.

Behavior↗
PubMed1976

International collaborative study of the spinal muscular atrophies. Part 1. Analysis of clinical and laboratory data.

There is considerable variation in age of onset, though in over three-quarters of cases onset is before 4 years of age. A febrile episode, often of viral origin, may be present at the time of onset and might possibly be of aetiological significance, perhaps by precipitating the disease in a genetically predisposed individual. Reduced fetal movements and floopiness at birth are present in about one third of those cases where the onset is in early childhood. It would seem that when the onset is before 4 years of age, and particularly if the child has never been able to sit without support, the prognosis is much worse than in cases where the onset is after the age of 4 years. The proximal limb muscles are predominantly affected and muscle tone is usually reduced but pseudohypertrophy is uncommon. Rarely are the cranial nerves affected. Muscle fasiculations are present in about half the cases. Almost 10% of cases appear to be mentally retarded. With regard to the EMG findings, spontaneous activity, reduced full effort pattern increased potential amplitude and duration and increased motor unit territory appear to be the most reliable diagnostic criteria. Routine histological evidence of neurogenic atrophy seems to be a more reliable diagnostic criterion than muscle histochemistry. However, this may be only reflect the way in which the data were selected, that is, from cases where a muscle biopsy showed evidence of neurogenic atrophy on routine histology. Finally the serum level of creatine kinase is rarely very high and in more than half the cases it is normal. The CSF chemistry is always normal.

Creatine Kinase↗
PubMed1976

International collaborative study of the spinal muscular atrophies. Part 2. Analysis of genetic data.

Most of the cases in the present study are of the juvenile onset, proximal form of spinal muscular atrophy. The results of the study indicate that the majority of these cases are due to one or more autosomal recessive genes, with very few being inherited as a dominant trait. Affected individuals very widely in the severity of the disease. When 2 or more sibs are affected, they tend to be similar as regards severity, but there are a substantial number of sibships in which this is not so. The data are consistent with either a single gene, with a wide range of expressivity due to the effects of other genes and/or environmental influences, or 2 or more genes, but with considerable overlap in their expression.

Adolescent↗