Heritability of adult body height: A comparative study of twin cohorts in eight countries

A major component of variation in body height is due to genetic differences, but environmental factors have a substantial contributory effect. In this study we aimed to analyse whether the genetic architecture of body height varies between affluent western societies. We analysed twin data from eight countries comprising 30,111 complete twin pairs by using the univariate genetic model of the Mx statistical package. Body height and zygosity were self-reported in seven populations and measured directly in one population. We found that there was substantial variation in mean body height between countries; body height was least in Italy (177 cm in men and 163 cm in women) and greatest in the Netherlands (184 cm and 171 cm, respectively). In men there was no corresponding variation in heritability of body height, heritability estimates ranging from 0.87 to 0.93 in populations under an additive genes/unique environment (AE) model. Among women the heritability estimates were generally lower than among men with greater variation between countries, ranging from 0.68 to 0.84 when an additive genes/shared environment/unique environment (ACE) model was used. In four populations where an AE model fit equally well or better, heritability ranged from 0.89 to 0.93. This difference between the sexes was mainly due to the effect of the shared environmental component of variance, which appears to be more important among women than among men in our study populations. Our results indicate that, in general, there are only minor differences in the genetic architecture of height between affluent Caucasian populations, especially among men.

Accuracy of Mothers' Retrospective Reports of Smoking During Pregnancy: Comparison with Twin Sister Informant Ratings

Retrospective assessment of maternal smoking or substance use during pregnancy is sometimes unavoidable. The unusually close relationship of twin sister pairs permits comparison of self-report data versus co-twin informant data on substance use during pregnancy. Information about smoking during pregnancy has been gathered from a series of mothers from an Australian volunteer twin panel (576 women reporting on 995 pregnancies), supplemented in many cases by independent ratings of their smoking by twin sister informants (821 pregnancies). Estimates of the proportion of women who had never smoked regularly (56-58%), who had smoked but did not smoke during a particular pregnancy (16-21%), or who smoked throughout the pregnancy (16-18%), were in good agreement whether based on self-report or twin sister informant data. However, informants underreported cases who smoked during the first trimester but then quit (1-3% versus 7-9% by self-report). Women who smoked throughout pregnancy (by informant report) rarely denied a history of regular smoking (

A STR mutation in a heteropaternal twin case

A heteropaternal male twin case with two men being alleged fathers was investigated as requested by the Court. Up to 37 PCR-based polymorphic DNA systems were studied in this case which was complicated by a paternal ACTBP2 mutation detected in one twin. This is the first report on a STR mutation in a double paternity case where both biological fathers were indisputably identified. The STR systems enable the resolution of these complex genetic relationships even in a case where a mutation in one STR locus was encountered.

Twin Peaks como alegoria daimónica cinematográfica

For a long time the allegorical activity was considered dogmatic and equated with artistic fossilization, archaic religious propensity and lack of creativity. However, Walter Benjamin (1928) and Paul De Man (1969), among other illustrious thinkers, came to its defense, exalting, instead, its cryptic, hybrid and abstract nature, which, incidentally, are the main characteristics of modern art. “Twin Peaks – Fire Walk with Me” (David Lynch, 1992) is a wonderful object of analysis, despite being one of the most misunderstood films in the history of cinema. The fact that its narrative is a prequel to the cult television series “Twin Peaks” and incorporates many of the characters of that show, explicitly denigrating the moral image of the protagonist, Laura Palmer, brought about an intense rejection by the fans of the series, as well as the indifference of the cinephilic community in general. However, one must go deeper, in order to understand Lynch’s brave accomplishment and its artfulness. Indeed, the opus is a powerful cinematic allegory because it contains a double layer of metaphorical meaning, one of them being explicitly metacinematic. Thus, besides assuming itself as a filmic daimonic allegory, occurring in a spiritual universe of Good versus Evil, the film is also an authorial discourse on cinema itself. More specifically, it is an allegory of spectatorship, according to Robert Stam’s definition, where the existence and crossing over to “another side” duplicates the architecture of movie theatres and the psychic processes involved in film viewing.

Hepatitis C virus in monozygotic twins

A case of a pregnant patient with chronic hepatitis C who gave birth to monozygotic twins that were infected with HCV is reported. One of the newborns was positive for HCV-RNA in blood sample collected 12 hours after delivery. The other newborn was negative for HCV-RNA at birth, but was detected HCV viremia at three months of age. The results have led to the conclusion that one of the twins was probably contaminated in the intrauterine period, while the other acquired the infection in the perinatal period. Both were negative for HCV-RNA and for anti-HCV in the serum samples collected at nine months of age. The report describes the changes in the laboratory tests conducted in mother and twins until 29 months after delivery.

Fetal behavior and heart rate in twin pregnancy: a review

Fetal movements and fetal heart rate (FHR) are well-established markers of fetal well-being and maturation of the fetal central nervous system. The purpose of this paper is to review and discuss the available knowledge on fetal movements and heart rate patterns in twin pregnancies. There is some evidence for an association or similarity in fetal movement incidences or FHR patterns between both members of twin pairs. However, the temporal occurrence of these patterns seems to be for the most part asynchronous, especially when stricter criteria are used to define synchrony. The available data suggest that fetal behavior is largely independent of sex combination, fetal position, and presentation. Conversely, chorionicity appears to have some influence on fetal behavior, mainly before 30 weeks of gestation. There is preliminary evidence for the continuity of inter-individual differences in fetal activity and FHR patterns over pregnancy. Comparisons between studies are limited by large methodological differences and absence of uniform concepts and definitions. Future studies with high methodological quality are needed to provide a more comprehensive knowledge of normal fetal behavior in twin pregnancy.

Genetic and Environmental Effects on the Abdominal Aortic Diameter Development

Abstract Background: Configuration of the abdominal aorta is related to healthy aging and a variety of disorders. Objectives: We aimed to assess heritable and environmental effects on the abdominal aortic diameter. Methods: 114 adult (69 monozygotic, 45 same-sex dizygotic) twin pairs (mean age 43.6 ± 16.3 years) underwent abdominal ultrasound with Esaote MyLab 70X ultrasound machine to visualize the abdominal aorta below the level of the origin of the renal arteries and 1-3 cm above the bifurcation. Results: Age- and sex-adjusted heritability of the abdominal aortic diameter below the level of the origin of the renal arteries was 40% [95% confidence interval (CI), 14 to 67%] and 55% above the aortic bifurcation (95% CI, 45 to 70%). None of the aortic diameters showed common environmental effects, but unshared environmental effects were responsible for 60% and 45% of the traits, respectively. Conclusions: Our analysis documents the moderate heritability and its segment-specific difference of the abdominal aortic diameter. The moderate part of variance was explained by unshared environmental components, emphasizing the importance of lifestyle factors in primary prevention. Further studies in this field may guide future gene-mapping efforts and investigate specific lifestyle factors to prevent abdominal aortic dilatation and its complications.

What is the most relevant standard of success in assisted reproduction?: The cumulated singleton/twin delivery rates per oocyte pick-up: the CUSIDERA and CUTWIDERA.

National and international registries are essential tools for establishing new standards and comparing success rates, but they do not take into account the total pregnancy/delivery rate per oocyte recovery. In Switzerland and Germany, because of legal constraints, a maximum of three two-pronuclear zygotes are allocated for transfer whereas all the supernumerary pronuclear zygotes are immediately cryopreserved, preventing selection of the transferred embryos. We report on a 10 years' experience (1993-2002) of our centre which performs transfers of unselected embryos and cryopreservation at the two-pronuclear zygote stage. As approximately 30% of all deliveries are from cryo cycles, it is essential to take into account the contribution of the cryo transfers, and we propose therefore to evaluate, as a measure of IVF performance, the cumulated delivery rate per oocyte pick-up. This delivery rate is broken down further into the cumulated singleton delivery rate (CUSIDERA) and the cumulated twin delivery rate (CUTWIDERA). The sum (S) of these two rates is a measure of efficacy while the ratio CUTWIDERA/S as a percentage is a measure of safety of IVF treatments. Using these new indexes, the average 10 year efficacy and safety of our IVF programme were 26 and 19%, respectively. Both CUSIDERA and CUTWIDERA can be calculated easily in any clinical situation and yield useful parameters for patient counselling and internal/external benchmarking purposes.

13q deletion syndrome and retinoblastoma in identical dichorionic diamniotic monozygotic twins.

PURPOSE: To report the case of identical dichorionic diamniotic female twins with unilateral retinoblastoma in 13q deletion syndrome. METHODS: Clinical and ophthalmoscopic evaluation, combination of multiple ligation-dependent probe amplification, array-comparative genomic hybridization analyses, and magnetic resonance imaging were performed. RESULTS: Peculiar facial features, marked hypotonia, gastroesophageal reflux, interatrial septal defect with left to right shunt and light dilatation of right chambers, 5th finger hypoplasia, 3rd-5th toes clinodactyly, 2nd toe overlapped to 3rd toe, and cutis marmorata were found. Ophthalmoscopic evaluation revealed unilateral retinoblastoma in both girls. Magnetic resonance imaging detected corpus callosum hypoplasia in both twins. A 34.4-Mb deletion involving bands 13q13.2-q21.33 and including the RB1 gene was identified in both twins. The deletion was not present in the DNA of their parents and older brother. CONCLUSIONS: Dysmorphic features in children must be always suspicious of 13q deletion syndrome and a short ophthalmoscopic follow-up is necessary to detect the presence of a retinoblastoma.

Bases genètiques de la malformació de Chiari

La Malformació de Chiari tipus I (MCI) ha estat definida tradicionalment com la herniació de les amígdales cerebel•loses d’almenys 5mm, a través del forat mange. En general, els símptomes es posen de manifest durant la segona o tercera dècada de vida, tot i que s’han descrit casos pediàtrics. Donada la complexitat del quadre clínic, per realitzar un diagnòstic adient es requereix avaluació clínica i estudi de neuroimatge. La tècnica de preferència és la ressonància magnètica d’imatge, considerant-se actualment com a pacients de MCI aquells que presenten un descens de les amígdales superior a 3mm per sota del forat magne. L'existència de casos asimptomàtics dificulta establir una prevalença concreta, però s’ha estimat que podria estar entre 1/1000 a 1/5000 sent major en dones que en homes (2:1 aproximadament). Fins el moment, es desconeix l’etiologia de la malaltia però la hipòtesi més acceptada és que MCI és deguda al desenvolupament insuficient del mesoderm paraxial. Diferents estudis realitzats fins el moment evidencien que almenys, un subgrup de pacients amb MCI són deguts a contribució genètica: 1) casos d’agregació familiar amb afectes en tres generacions; 2) estudis de bessons 3) associació amb síndromes genètics coneguts amb herència mendeliana produïts per anomalies óssies que donen suport a la hipòtesi de la insuficiència del mesoderm com a causa de MCI. Davant l’evidència clara d’un component genètic com a principal causant de l’etiologia de MCI, l’objectiu del projecte va ser la identificació de les bases genètiques de la MCI, tant en gens responsables de les formes mendelianes com en gens responsables de les formes complexes de MCI mitjançant dues estratègies: 1-Identificació de variants genètiques de susceptibilitat en pacients amb MCI mitjançant estudis d’associació de tipus cas-control. 2-Anàlisi genètic de formes monogèniques mitjançant l’anàlisi de lligament a marcardors polimòrfics i la seqüenciació del DNA a gran escala.

Anorectal malformation and Down's syndrome in monozygotic twins.

Anorectal malformation (ARM) can be divided in high, intermediate, and low forms according to the level of termination of the rectum in relation to the pubococcygeal and ischiatic lines. Patients with Down's syndrome have a high incidence of gastrointestinal anomalies, such as tracheoesophageal fistula, duodenal obstruction, annular pancreas, Hirschsprung's disease, and ARM. In these children, ARM is generally low with or without a fistula. The mode of inheritance of ARM and its genetic relation with Down's syndrome is not known, even if the association (ARM-Down's syndrome) seems not to be coincidental. We describe here a very rare case of monozygotic twins born with the association of ARM and Down's syndrome.