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J Stene

Publications and source records attributed to J Stene.

At least 37 records · Page 2Linked to original sources
PubMed1978

Choice of ascertainment model I. Discrimination between single-proband models by means of birth order data.

A statistical method for choosing between ascertainment models for human family data has been constructed. The families are assumed to have been ascertained through a single proband each and the birth number of the proband among the affected children is recorded. If the proband is the eldest affected child in each family the so-called complete ascertainment model has to be used. If each affected child has the same probability of being the proband, the so-called single ascertainment model should be used. In intermediate cases a third ascertainment model should be used.

Birth Order↗
PubMed1978

On data and methods in investigations on parental-age effects. Comments on a paper by J. D. Erickson.

An analysis of the NIS data used by Erickson (1977) has revealed that this data contains too few Down's syndrome cases with older fathers. Thus the data is less suited for an investigation of a possible paternal age effect. In addition, the statistical tests used by Erickson have low power, so that they are unable to detect a moderate paternal-age effect. Our analysis has demonstrated that discussions on paternal-age effects and similar problems should be based on high-quality data. The investigation is better based on a small high-quality material than on a large one with serious underascertainment. In the latter case one has to be extremely careful because the missing observations nearly always have common characteristics which may cause serious bias of relevant kinds.

Adult↗
PubMed1978

Ascertainment models for human families selected through several affected children.

Sampling models for families having normal and affected children and being selected through information about two or more of the affected ones have been developed. Such a model, a so-called ascertainment model, yields the conditional probability that a family has r affected children given that it has s children altogether and that it has been selected or ascertained with a probability which is proportional to a given power of the number of different groups of m less than or equal to r affected children. When the power equals zero or one the model is simplified considerably. If also m = 1 we get the well-known complete ascertainment and single ascertainment model as special cases.

Child↗
PubMed1977

Risk for short arm 10 trisomy. A segregation analysis of eleven families with different translocations.

A segregation analysis has been carried out for 11 families with trisomy 10p caused by familial translocations involving a segment of the short arm of chromosome 10. The theoretical basis for the analysis is considered in some detail. No differences were found between the segregation pattern in the offspring of carrier mothers and that of carrier fathers. There was a high risk for offspring with trisomy 10p (22%). A phenotypically normal descendant also has a high risk of becoming a balanced translocation carrier (71%). This result does not deviate significantly from the theoretical value of 50%.

Chromosomes, Human, 6-12 and X↗
PubMed1977

New chromosomal dysmorphic syndromes. 2. Trisomy 10p.

This is the report of a family in which a balanced translocation in the mother t(5;10)(p15;p13) led to an unbalanced chromosomal constitution in two children. It was identified by G-banding analysis as trisomy of the distal portion of the short arm of chromosome 10 (p13 leads to pter). Comparison with 15 previous reports of trisomy 10p confirms the existence of a characteristic dysmorphic syndrome.

Abnormalities, Multiple↗
PubMed1977

Psoralen/UVA treatment and chromosomes. I. Aberrations and sister chromatid exchange in human lymphocytes in vitro and synergism with caffeine.

Treatment of human lymphocytes in vitro with trimethylpsoralen or 8-methoxypsoralen and UVA irradiation (PUVA) induced chromosome damage, mainly constrictions and gaps, but also breaks and exchanges, and increased the frequency of sister chromatid exchange (SCE). The localization of the chromosome aberrations was nonrandom. The coincidence of many PUVA hits with mercaptoenthanol hits suggest that PUVA may have other targets in the cell than the DNA, perhaps the folding proteins of the chromosomes and the nuclear membrane/chromatin attachment organelles. Caffeine increased in a synergistic way the chromosome aberration yield if added after PUVA treatment, but there was no effect when caffeine was present before and during PUVA treatment. The SCE frequency was increased in the presence of caffeine.

Caffeine↗
PubMed1977

Paternal age effect in Down's syndrome.

Increasing incidence of Down's syndrome with advancing paternal age for given maternal age has been demonstrated. Comparisons are made between an almost complete Down's syndrome sample from the Copenhagen Metropolitan Area and a randomly selected sample of births from the same area and the same time period. Men above 55 years have a significantly increased risk of getting children with Down's syndrome.

Adolescent↗
PubMed1977

Statistical methods for detecting a moderate paternal age effect on incidence of disorder when a maternal one is present.

A statistical method is developed for detecting a moderate effect on the incidence of a disorder caused by advancing age of one parent when it is known that advancing age of the other parent is of great aetiological importance. The method is a conditional test procedure given the parental ages, therefore no assumptions about the parental age distributions have to be made. The method is applied on Danish material on Down's syndrome, for which a paternal age effect is demonstrated. Methods used in some well-known previous investigations have been discussed. Several of them, e.g. the classical one of Penrose (1933), could hardly detect any paternal age effect in Down's syndrome on the available data, because these methods are heavily affected by certain fertility patterns not recognized previously.

Denmark↗
PubMed1977

Assumptions for different ascertainment models in human genetics.

Some aspects of sampling family data in human genetics are discussed. Two well-investigated ascertainment models, the complete ascertainment model and the single ascertainment model, which have been derived using restrictive sampling assumptions, are shown to hold under four more general sets of assumptions.

Genetic Diseases, Inborn↗
PubMed1976

Incidence study of Down's syndrome in Copenhagen, 1960-1971; with chromosome investigation.

The aim of the study was to obtain incidence figures for Down's syndrome throughout a period where a considerable change in the age distribution of child-bearing mothers has taken place and to study if the expected fall in incidence has occurred. In parts of the Copenhagen Metropolitan area 235 liveborn patients with Down's syndrome were ascertained in the period 1960 to 1971 in a population of 1-2 million with a total of 204771 births. All patients available were examined cytogenetically (75%). In 160 (90-4%) a regular trisomy 21 was observed. In 6-2% of the cases translocations and in 2-3% of the cases mosaics were found. Two double trisomies and a double trisomy mosaic were observed. Throughout the period 1960-71 the percentage of women over 30 years delivering children decreased from 23-4% in the beginning of the period to 16-2% at the end of the period. In the first part of the period 52-6% of the cases were born to mothers over 30, at the end of the period 40% of Down's syndrome mothers were of that age. However, the incidence was unchanged throughout the whole period, about 1-15 per 1000 births. For some age groups a steady rise in incidence of trisomy 21 cases was found throughout the whole period. These findings may be explained by better ascertainment of patients at the end of the period; however, environmental factors may also play a role.

Adolescent↗
PubMed1975

Sibships ascertained through a twin pair with at least one affected twin.

For sibships ascertained through a twin-pair where at least one of the twins is affected, an exact conditional test is developed for the hypothesis that the probability for a dizygotic twin to be affected is equal to that of single-born children against the alternative that the probability is higher among twins. Such a situation may occur in disorders where a twin pregnancy may cause sporadic cases of non-genetic origin. The method has been applied to data on febrile convulsions. It is shown that dizygotic twins with a family history of the disorder are more likely to get febrile convulsions than their single-born sibs. I want to thank DR M. Lennox-Buchthal, M.D., Copenhagen, for providing me with data and histories.

Diseases in Twins↗