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At least 19 recordsLinked to original sources

PubMed1976

Congenital toxoplasmosis in twins: a series of 14 pairs of twins: absence of infection in one twin in two pairs.

Fourteen pairs of twins with congenital toxoplasmosis were observed. In two pairs, one twin was infected and had symptoms of chorioretinitis or encephalomyelitis, while the other had a negative dye test upon repeated examination: this phenomenon has not previously been reported. In three of the other twelve pairs of twins, one of each pair died; two of them had evidence of toxoplasmosis; in the cotwin the diagnosis was based on serologic data. Clincial and biologic follow-up extended from 19 months to 8 years in five pairs. Marked discrepancies in the individual clinical patterns of the two children in each of six sets of twins were observed, with evidence of infection in one twin and subclinical infection in the other. These clinical findings correlated well with serologic data in the children in whom sufficient follow-up was permitted. The clinical pattern of congenital toxoplasmosis in twins is extremely similar in monochorial pregnancies, but discrepancies are almost the rule in bichorial pregnancies. The importance of placental lesions in determining the extent of fetal involvement is well illustrated by studies of toxoplasmosis in twins.

Child↗

PubMed1976

Outcome of twin birth. Review of 1,636 children born in twin birth.

During the five-year period 1964-68 96 733 births were registered in the 28 hospitals equipped with maternity facilities in the Uppsala hospital region. Of these babies, 1 636 were born in 818 twin deliveries. Data on gestational age, sex, weight and length at birth, birth order, hospital type, congenital malformations and perinatal mortality are analysed. Altogether 17.3 per 1 000 of the children born during this period were born in multiple births. The perinatal mortality for the twin babies was 64 per 1 000 born, with the mortality higher in the less specialized hospitals than the others. Twin no. 1 suffered perinatal death in 67 cases per 1 000 and twin no. 2 in 60 cases per 1 000. For twins of primiparae the losses were 92 per 1 000 children and for twins born to multiparae 51 per 1 000. Altogether 72 per 1 000 male twins died perinatally compared to 52 per 1 000 female twins. The most heavy losses occurred among the low-weight premature twins and in these cases both twins often suffered perinatal death.

Birth Weight↗

PubMed1976

[Heredity of twinning in families of monozygotic twins (author's transl)].

Whereas the existence of some genetic factor underlying the phenomenon of twinning is almost generally accepted with respect to DZ twins, no such agreement exists with respect to MZ twins. The possible existence of genetic factors underlying MZ twinning has been verified through an analysis of segregation in the sibships of MZ twins and in those of their parents, carried out on a sample of 57 MZ twin pairs (30 M and 27 F). Haldane's a priori method has been applied, considering the sample as obtained through a complete and through an incomplete ascertainment. The results may lead to cautiously confirm the hypothesis of some genetic conditioning of MZ twinning.

Alleles↗

PubMed1978

A twin analysis of dietary intake: evidence for a need to control for possible environmental differences in MZ and DZ twins.

In the NHLI Twin Study MZ twins are shown to "get together" substantially more often than DZ twins. With this result as an indicator of differences in shared environment, the assumption of equal shared environmental variation for MZ and DZ twins is assessed using nutritional data calculated from a food frequency questionnaire. Six nutrients show significant genetic variance for the total sample. However, when stratified on the basis of how frequently twins see each other, none of the nutrients shows significant genetic variance for both strata. A similar pattern is seen for several individual items from the questionnaire. In addition, four of the nutrients show significant correlation between the absolute difference in the nutrient intake of MZ twin pairs and how often they "get together." These data appear to show that unequal environmental effects may lead to falsely high estimates of genetic variance for nutrient intake.

Adult↗

PubMed1992

The fate of "small twins": a four-year follow-up study of low birthweight and prematurely born twins.

This follow-up study of twins includes 35 families from the Stockholm area. One section concerns the physical and mental development of the twins. The other sections compare the development of the children with their parents' expectations of them and the parents' feelings about the delivery. Seven twin pairs (20%) in the total group were born before 37 complete gestational weeks. Thirty-seven of the twins weighed less than 2,500 g at birth; of these, 23 (9 boys and 14 girls) weighed less than 2,500g, although they were born after 37 gestational weeks. At four years of age, 22 of the 68 twins still showed some impairment of locomotor, language/speech and emotional development, as assessed by the Griffiths Mental Development Scales. All the prematurely born and small-for-date infants were in this group. There also seems to be a relationship between developmental problems and the mother's negative or ambivalent expectations concerning the twin pregnancy.

Age Factors↗

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↗

PubMed1979

alpha1-Antitrypsin deficiency in twins and parents-of-twins.

Serum-trypsin-inhibitory-capacity (STIC) and alpha1-antitrypsin (AAT) genotypes were evaluated in 83 twins and 112 paired parents-of-twins. An increased prevalence (17.0--21.9%) of intermediate AAT deficiency (STIC less than 0.95 units/ml) was detected in both of these groups as compared to a prevalence of 4.1% in 1,841 healthy controls. PiS and PiZ molecular variants of AAT were also found more frequently in the twin and parent groups, but this was not statistically significant. Low levels of protease inhibition may enhance fertility and a tendency towards twinning, since proteolytic enzymes are involved in fertilization of ova by sperm and in gametogenesis. Increased fertility and twinning may be heterozygous advantages for AAT deficiency.

Female↗

PubMed1979

Sonar cephalometry in twins: a table of biparietal diameters for normal twin fetuses and a comparison with singletons.

In 123 normal twin pregnancies, 589 biparietal diameter (BPD) measurements were obtained between 16 and 40 weeks' gestation and mean values for each week were computed. A table of BPDs for normal twin pregnancies based on these data is proposed. Mean twin BPDs were consistently smaller than those of singletons, the difference averaging 3.5 mm between 16 and 40 weeks' gestation. The development of a twin BPD table now permits a more accurate assessment of twin gestational age and fetal growth.

Cephalometry↗

PubMed1992

Effects of early mother-twin relationships from birth to age 3, on twin bonding.

Findings from an earlier phase of this research project clearly pointed to the mother's psychological adaptation inherent to the specificities of triadic interaction. Mothers' attitudes were classified in a typology ranging from "early twinness" where the two babies are treated as though they were a single unit, to attempt to create two dyadic relationships. The current program deals with the effects of the type of parent-child relationship at one year on the emergence of twin bonding. Sixty-eight families of twins (26MZ, 24DZ same sex, 18DZ different sex) are followed up from birth to the age of 3 using a method based on clinical interviews, videotaped observations, and questionnaires. The data cover mothers' rearing attitudes towards organization of babycare and outward signs of twinness, maternal representations of the relationship between the twins and observation of the children's interaction in a standardized game situation. The findings are discussed in terms of zygosity, and parental SCS.

Attitude↗

PubMed1979

Testing twin means and estimating genetic variance: basic methodology for the analysis of quantitative twin data.

Twin methodology for the analysis of continuously distributed traits is presented as a guideline for initial steps in the analysis of twin data. Tests for heterogeneity of twin means and variances are reviewed along with estimates of genetic variance. Analysis of twin data appears on the surface to be a rather simple task, but investigators may well be confused by the wealth of choices available for hypothesis testing. This paper is designed to help the less experienced investigator, with perhaps a modest amount of data, begin analysis with maximum attention to testing all testable assumptions of the twin model, and using recent examples of applications of the methods.

Female↗

PubMed1976

[Psychopedagogic counseling for twins and twin families (author's transl)].

In 1973 the Mendel Institute, within the specialized services it offers to Italian twins, instituted psychopedagogic counseling for twins and their families. This service is carried out in the intermediate field between neuropsychiatry and social work. Cases involving family and social maladjustment were referring for counseling. During the academic year 1973-1974, the service examined 96 cases, of which 58 involved problems of school retardation and 38 involved family maladjustment because of changed parent-twin relationships. The counseling service aimed at achieving improved family and school relationships by means of various therapeutic interventions. The psychopedagogic counseling, besides the immediate therapy, has permitted deeper study of maladjustment by means of analyses of the twins' condition as a possible additional cause of the maladjustment itself. Analysis of the cases in this limited sample would seem to indicate an indirect incidence of the twin situation per se (couple effect), somewhat emphasized by the family and social environment.

Adolescent↗

PubMed1978

[Pregnancy and labor in twins. II. Determination of twin pregnancy and avoidance of premature birth (author's transl)].

In about 65% of the 258 twin births which occurred at the University Gynaecological Hospital, Zürich, from 1966 to 1976, it was possible to diagnose the twin pregnancy before the birth of the first twin. Twin pregnancy could be diagnosed in 96.2% of all the cases before the birth of the first twin, after routine ultrasound diagnosis of pregnancy had been introduced. Prerequisite of optimal treatment of pregnancy is a very early diagnosis which is only possible by widest use of ultrasound investigation technique. The rate of premature births was reduced from 48.0% to 27.3% by means of complete rest in bed and prophylactic tocolysis with a betamimetic from the 32nd to the 37th week of pregnancy. At the same time, the number of underweight children below 2.500 g was reduced by means of this treatment from 60.1% to 34.1%. It seems to be an undisputable fact that prolonged hospitalization in the last three months of pregnancy will improve the prognosis.

Adrenergic beta-Agonists↗

PubMed1977

Psychophysiologic test performance in normal twins and in a pair of identical twins with essential tremor that is suppressed by alcohol.

In a sample of 52 adults male twin pairs (26 MZ, 26DZ) performance in a series of psychophysiologic tests was measured. The intraindividual variability was determined by repetitive tests in the same subjects. In a number of cases the measured parameters proved relatively stable within the same peron; identical twins, however, were no more similar to one another than fraternal twins. In a pair of identical twins with autosomal-dominant essential tremor the degree of the tremor could be effectively reduced by alcohol application.

Adult↗

PubMed1977

Cytogenetic investigation in twins with manic-depressive disorders (22 monozygotic and 27 dizygotic twin pairs).

Chromosome examination was made in 22 monozygotic and 27 dizygotic twin pairs of whom one or both of each pair suffered or had suffered from manic-depressive disorder. We found a significantly higher frequency of chromosome variations among dizygotic twin pairs than was expected from population studies, but not in monozygotic pairs. There was no association between the chromosome variations and manic-depressive disorders. We found no greater intra-pair correlation in monozygotic twins compared with dizygotic twins as regards hypodiploidy, hyperdiploidy and unstable chromosome aberrations, which indicates that the aetiology of such aberrations is mainly of exogenic nature.

Bipolar Disorder↗

PubMed1979

Appraisal of parental bias in twin studies. Ascribed zygosity and IQ differences in twins.

A criticism of twin studies has been that the difference between the behavioral similarities of identical and fraternal twins is largely created by parental influences based on their perception of the twins' zygosity. This issue is examined for differences in the IQ scores found within pairs classified by parents and bloodtyping. The systematic differences in IQ scores could be attributed to zygosity classified by bloodtyping rather than by parental belief. The available evidence indicates that the twin method is still appropriate for human behavior genetics.

Blood Grouping and Crossmatching↗

PubMed1979

Twin azygotic test for the study of hereditary qualitative traits in twin populations.

Following previous formulations of a model of qualitative analysis of twin population data independent of zygosity, a new Bayesian approach has been developed. The present model can be applied to any qualitative genetic trait in twin population data, provided no specific source of variation be introduced by the twin condition, and allows not only estimation of the frequencies of mono- and dizygosity as well as the gene frequencies, but also verification of the trait's mode of inheritance.

Bayes Theorem↗

PubMed1979

The Northwestern University Multihospital Twin Study. II. Mortality of first versus second twins.

The results of a multihospital study involving a total of 588 twin pairs born in Chicago in 1970-1975 are reported, with special respect to differences in mortality between first and second twins by time as well as by cause of death. Mortality was higher in second than in first twins and most commonly occurred after delivery and was the result of immaturity and of respiratory distress syndrome.

Asphyxia Neonatorum↗

PubMed1977

Physiomorphology of twin transfusion syndrome. A study of 86 twin gestations.

The placentas of 86 pairs of twins were examined and correlated with the clinical characteristics of the neonate. The incidence of twin pregnancy in this group was 1 : 108 deliveries. Fetal prematurity and associated complications in twin pregnancy were the cause of increased perinatal and neonatal mortality.

Adult↗