The genetic-environmental etiology of parents' perceptions and self-assessed behaviours toward their 5-month-old infants in a large twin and singleton sample

BACKGROUND: Given the importance of parenting for the child's early socio-emotional development, parenting perceptions and behaviours, and their correlates, should be assessed as early as possible in the child's life. The goals of the present study were 1) to confirm, in two parallel population-based samples, including a large sample of twins, the factor structure of a new self-administered questionnaire assessing both parents' specific parenting perceptions and behaviours toward their 5-month-old infants (i.e., parental self-efficacy, perceived parental impact, parental hostile-reactive behaviours and parental overprotection), 2) to identify the specific risk factors associated with the negative side of these parenting dimensions, 3) to document the genetic-environmental etiology of these parenting dimensions through the twin method. METHODS: Parents (2,122 mothers and 1,829 fathers) of 5-month-old infants, and parents of 5-month-old infant twins (510 families) completed the questionnaire (28 items). The data were submitted to a series of confirmatory factor analyses. The contribution to parenting of a variety of risk factors was examined in the two samples using regression analyses. A series of quantitative genetic analyses were performed to quantify the different sources of variation in parenting. RESULTS: A consistent factor structure was found across informants and across samples. There were significant mean differences in parenting between mothers and fathers, as well as between parents of twins and parents of singletons. A differentiated pattern of association with risk factors was found for each dimension of parenting. The twin analyses revealed that shared environment accounted for each parenting dimension. Maternal hostile-reactive behaviours were also moderately related to genetic factors in the child and this association was mainly mediated by the infant difficultness. CONCLUSIONS: The overall pattern of results was consistent with Belsky's (1984) view of parenting as multiply determined. The longitudinal follow-up of these families should provide the means for testing developmental models about the determinants and outcomes of these parenting dimensions.     

Genetic components of functional connectivity in the brain: the heritability of synchronization likelihood

Cognitive functions require the integrated activity of multiple specialized, distributed brain areas. Such functional coupling depends on the existence of anatomical connections between the various brain areas as well as physiological processes whereby the activity in one area influences the activity in another area. Recently, the Synchronization Likelihood (SL) method was developed as a general method to study both linear and nonlinear aspects of coupling. In the present study the genetic architecture of the SL in different frequency bands was investigated. Using a large genetically informative sample of 569 subjects from 282 extended twin families we found that the SL is moderately to highly heritable (41-67%) especially in the alpha frequency (8-13 Hz) range. This index of functional connectivity of the brain has been associated with a number of pathological states of the brain. The significant heritability found here suggests that SL can be used to examine the genetic susceptibility to these conditions.     

A Case of Hypoplastic Left Heart Syndrome and Bicuspid Aortic Valve in Monochorionic Twins

The etiology of hypoplastic left heart syndrome (HLHS) remains unclear. Since a genetic cause for HLHS has not been obvious, it is generally considered to be inherited in a multifactorial manner. Studies of twins are valuable in elucidating the genetic contribution to a birth defect such as HLHS. We report a case of monochorionic twins in whom one has HLHS and the other has a bicuspid aortic valve. Predisposing genetic and environmental influences on individuals with identical genotypes, such as twins, may result in discordance of left-sided flow lesions.     

Multicystic encephalomalacia after first-trimester intrauterine fetal death in monochorionic twins

Multicystic encephalomalacia occurs in approximately 20% of surviving cotwins after second- and third-trimester intrauterine fetal death of one twin in monochorionic pregnancies. We report a case of multicystic encephalomalacia after the demise of a cotwin in the first trimester diagnosed by magnetic resonance imaging and confirmed pathologically.     

Radiofrequency ablation in a monochorionic twin discordant for fetal anomalies

Radiofrequency ablation is a minimally invasive technique that has been used in selective reduction of acardiac twins. We report a case in which radiofrequency ablation was used to selectively reduce a monochorionic twin discordant for an abnormality.     

Cardiac and other malformations in parapagus twins

Introduction Conjoined twins occur in one in 50–200,000 live births and approximately 75% of all cases are thoracopagus twins. Parapagus conjoined twins are rare and are not included in many review articles.Case report The cardiovascular system of a male parapagus (dicephalus, tetrabrachius, dipus) conjoined twins was studied. Twin B had bilateral bilobed lungs and a normal heart, while bilateral trilobed lungs and right isomerism was found in twin A. They shared a diaphragm and an abdominal cavity. There were two complete heads on two necks, two thoraxes, one abdomen, four arms, two legs, two complete vertebral columns, a single pelvis, and severe cardiac anomalies.     

Monozygotic Twins and Triplets in Association with Blastocyst Transfer

PURPOSE: To compare the incidence of monozygotic twins following blastocyst versus day-3 embryo transfer (ET). METHODS: A retrospective analysis of the outcome of assisted reproductive technology (ART) cycles utilizing blastocyst ET during 1999-2000 was compared to a similar group of patients undergoing day-3 ET during 1997-1998. RESULTS: Blastocyst ET was used in 75 cycles with 2.0 +/- 2 embryos transferred. The comparison group consisted of 90 cycles with day-3 ET and 3.0 +/- 2 embryos transferred. CONCLUSIONS: High pregnancy rates are maintained with blastocyst ET even though fewer embryos are transferred. The rate of monozygotic twins is higher with blastocyst ET than with day-3 ET. This increase may partially negate the benefit of reduced high-order multiple gestations attributed to blastocyst ET.     

Identical reconstitution after bone marrow transplantation in twins who received fresh and cryopreserved grafts harvested at the same time from their older brother

We report here the reconstitution after bone marrow transplantation (BMT) in identical infant twins with acute myelogenous leukemia (AML). They were diagnosed at 8 and 9 months of age. Complete remission was induced after two courses of chemotherapy. After four and five courses of chemotherapy, respectively, they received BMT at 2-month interval from the same HLA-identical older brother. The total dose of marrow nucleated cells (NC) harvested was 77.7 x 10(8). The first patient was transplanted with half of the total dose of NC. The remaining cells were cryopreserved without the use of a programmed freezer and transplanted into the second patient 2 months later. The number of days for neutrophil (>0.5 x 10(9)/L), platelet (>50 x 10(9)/L), and reticulocyte (>1%) recovery were, respectively, 15, 21, and 14 in the first case and 12, 21, and 15 in the second case. The clinical courses after BMT were uneventful in both cases, except for mild acute GVHD, and complete remission has been maintained >4 yr with full recovery of immune and marrow function. Based on the results in these cases, we confirmed that marrow cells that have been cryopreserved without the use of a programmed freezer could reconstitute immune and marrow function as well as non-cryopreserved cells.     

Advanced “tactile” medical imaging for separation surgeries of conjoined twins

Background Understanding the anatomy of conjoined twins is difficult because of the rarity of this congenital malformation and the scarcity of reported cases in medical literature.New technology Advances in radiologic imaging, computer modeling, and sophisticated manufacturing techniques enable medical imaging datasets to be translated into accurate, solid, life-size models. These models, which can be designed to include various combinations of anatomical features revealed by established imaging modalities, are important for pre-surgical assessments and planning, as well as for reference during the actual operative procedure. In addition, they provide a valuable basis for communication between the groups of specialists who are involved in these cases.Case studies This article will describe the advances in technology behind this process and illustrate its value in two cases of craniopagus twins.