The Population-Based Hungarian Twin Registry: An Update.

Between 2006 and 2021, the Hungarian Twin Registry (HTR) operated a volunteer twin registry of all age groups (50% monozygotic [MZ], 50% dizygotic [DZ], 70% female, average age 34 ± 22 years), including 1044 twin pairs, 24 triplets and one quadruplet set. In 2021, the HTR transformed from a volunteer registry into a population-based one, and it was established in the Medical Imaging Centre of Semmelweis University in Budapest. Semmelweis University's innovation fund supported the development of information technology, a phone bank and voicemail infrastructure, administrative materials, and a new website was established where twins and their relatives (parent, foster parent or caregiver) can register.

The Hungarian Twin Registry Update: Turning From a Voluntary to a Population-Based Registry.

Since our last report on the voluntary Hungarian Twin Registry (HTR) in 2012, the number of pairs or multiplets included increased from 310 to 1044. Efforts to turn the registry into a population-based one are on the way. Nearly 128,000 twins living in Hungary (98,500 adults) will be mailed information on how to register on the new HTR website.

Arsenic in drinking water and congenital heart anomalies in Hungary.

Inorganic arsenic can get easily through the placenta however there are very few human data on congenital anomalies related to arsenic exposure. Objective of our study was to explore the associations between arsenic content of drinking water and prevalence of some congenital anomalies. Four anomalies reported to the Hungarian Congenital Anomalies Registry between 1987 and 2003 were chosen to be analysed in relation to arsenic exposure: congenital anomalies of the circulatory system (n=9734) were considered as cases, while Down syndrome, club foot and multiple congenital malformations were used as controls (n=5880).

Bioimpedance analysis of body composition in an international twin cohort.

Objective: Multiple twin studies have demonstrated the heritability of anthropometric and metabolic traits. However, assessment of body composition parameters by bioimpedance analysis (BIA) has not been routinely performed in this setting.

Design: A cross-sectional study.

50 years of the Hungarian Congenital Abnormality Registry.

The mandatory notification of patients ("cases") with different congenital abnormalities (CAs) diagnosed from birth until the end of the first postnatal year by medical doctors was ordered by the Ministry of Health in Hungary in 1962 and this CA-registry was continued as the Hungarian Congenital Abnormality Registry (HCAR) based on the international recommendation from 1970. The primary objective of the HCAR has been to determine the baseline birth prevalence rate of different CAs as reliably as possible, with three secondary objectives: (i) to detect temporal and/or spatial clusters of CAs; (ii) to evaluate increasing or decreasing time trends of CAs; and (iii) to assist in the planning of medical and social services for children and families affected by CA so that appropriate resources are allocated efficiently and effectively. This paper summarizes the activities and the evolution of the HCAR over the past 50 years (1962-2011) including the Hungarian Case-Control Surveillance of Congenital Abnormalities for postmarketing surveillance of drug teratogenicity and prevention of CAs; the special evaluation of unidentified multiple CAs; the Hungarian Surveillance of Germinal Mutations and several international collaborations.

Genetic impact dominates over environmental effects in development of carotid artery stiffness: a twin study.

Arterial stiffness is an independent predictor of cardiovascular, cerebrovascular and all-cause mortality. Quantifying the genetic influence on the stiff arterial phenotype allows us to better predict the development of arterial stiffness. In this study, we aimed to determine the heritability of carotid artery stiffness in healthy twins.

[Hungarian twin studies: results of four decades].

Twin studies play a role in examining the contribution of genetic variations and environmental factors responsible for the determination of phenotypic variables and of genetic linkage between genotypes. Hungarian twin studies, supported by three twin registries (among them two twin-database), date back to 1970s. Studies mainly focused on various congenital abnormalities, the effect of contraceptive pills and folic acid on the frequency of twin pregnancies, as well as psychosexual and alcohol consumptional behaviors.

Trends in the prevalence, risk and pregnancy outcome of multiple births with congenital anomaly: a registry-based study in 14 European countries 1984-2007.

Objective: To assess the public health consequences of the rise in multiple births with respect to congenital anomalies.

Design: Descriptive epidemiological analysis of data from population-based congenital anomaly registries.

Setting: Fourteen European countries.

Evidence for a strong genetic influence on carotid plaque characteristics: an international twin study.

Background And Purpose: Few family studies reported moderate genetic impact on the presence and scores of carotid plaques. However, the heritability of carotid plaque characteristics remains still unclear. Twin studies more reliably estimate the relative contribution of genes to these traits in contrast to family study design.

The Hungarian Twin Registry.

The first Hungarian Twin Registry was established in Budapest in 1970 through the mandatory reporting of multiple-births. In the 1980s a second, volunteer adult registry was also founded. Unfortunately, both registries ceased to exist in the 1990s.

Heritability of central blood pressure and arterial stiffness: a twin study.

Objective: Central blood pressure and aortic stiffness have been consistently reported as strong cardiovascular risk factors. Twin studies by comparing identical with nonidentical twins produce information on the relative contribution of genes and environment.

Methods: One hundred and fifty-four monozygotic (MZ) and 42 dizygotic (DZ) twin pairs (age 43 ± 17 years) from Hungary and the United States underwent brachial and central augmentation index (AIx), brachial and central pressure, and aortic pulse wave velocity (PWV) measurements with the invasively validated Arteriograph device.

Effect of genetic and environmental influences on cardiometabolic risk factors: a twin study.

Background: Both genetic and environmental factors play a role in the pathogenesis of type 2 diabetes and cardiovascular diseases. The magnitude of genetic and environmental influences may vary in different populations and can be investigated by twin studies.

Methods: In this cross-sectional study, 101 (63 monozygotic and 38 dizygotic) adult twin pairs (n = 202; mean age: 44.

Conjoined twins: a worldwide collaborative epidemiological study of the International Clearinghouse for Birth Defects Surveillance and Research.

Conjoined twins (CT) are a very rare developmental accident of uncertain etiology. Prevalence has been previously estimated to be 1 in 50,000 to 1 in 100,000 births. The process by which monozygotic twins do not fully separate but form CT is not well understood.

[Heritability of the risk factors characteristic for the metabolic syndrome: a twin study].

Unlabelled: Both genetic and environmental factors play role in the pathogenesis of the metabolic syndrome. The magnitude of genetic and environmental influences on the components of metabolic syndrome may vary in different populations.

Aims: The present study was aimed to determine the effects of genetic and environmental factors on risk factors characteristic for the metabolic syndrome.

Effects of genetic vs. environmental factors on cardiovascular autonomic function: a twin study.

Aims: Cardiovascular autonomic function is often assessed in patients with diabetes by measuring heart rate variability and baroreflex sensitivity, the heritability of which is not fully understood. The present study was aimed to determine the effects of genetic and environmental factors on heart rate variability and baroreflex sensitivity in monozygotic and dizygotic adult healthy twin pairs.

Methods: A total of 101 (63 monozygotic, 38 dizygotic) adult twin pairs (n = 202; mean age 44.

Psychosexual study of communist era Hungarian twins.

Our aim in this study is to describe the characteristics of sexual development in twins and estimate the role of heritability and environmental factors as causes of certain sexual disorders. Two hundred and ten adult same-sex twin pairs (92 monozygotic [MZ] female, 41 MZ male, 55 dizygotic [DZ] female and 22 DZ male pairs) were involved in the study. Data were collected in 1982 by self-administered questionnaires that included items on sexual maturation, sexual life, contraception, mutual sexual activity within twin pairs and alcohol use.

Maternal demographic and socioeconomic characteristics of live-born infants with isolated ocular congenital abnormalities.

Purpose: To evaluate maternal age and birth order, in addition socioeconomic status and finally occupational background of mothers who delivered babies with different isolated ocular congenital abnormalities.

Methods: The data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-2002 was used and the evaluation of maternal variables was based on both medical records and maternal information.

Results: Mean maternal age and birth order was lower in the mothers of cases with isolated an/microphthalmia.

Gastroschisis and associated defects: an international study.

Our objective was to evaluate the frequency and type of malformations associated with gastroschisis in a large pool of international data, to identify malformation patterns, and to evaluate the role of maternal age in non-isolated cases. Case-by-case information from 24 registries, all members of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR), were evaluated. After the exclusion of other abdominal wall defects cases were classified as: (a) isolated; (b) recognizable syndrome, chromosomal or not; (c) multiple congenital anomalies (MCA).

Drug treatment during pregnancy and isolated orofacial clefts in hungary.

Objective: To evaluate the possible association between all kinds of drug treatments during pregnancy and isolated cleft lip with or without cleft palate (CL/P) and posterior cleft palate (PCP) in the offspring.

Setting: The dataset of the large population-based Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996, was evaluated.

Participants: One thousand three hundred seventy-four cases with isolated CL/P and 601 with PCP, plus 38,151 population controls (without birth defects) and 20,868 malformed controls with other defects.

Maternal employment status and isolated orofacial clefts in Hungary.

Aims: To study the role of maternal employment status as indicator of socioeconomic status in the origin of isolated orofacial clefts (OFC) and in the use of periconceptional folic acid/multivitamin supplementation.

Methods: 1,975 cases with OFC (1,374 cases with cleft lip +/- palate and 601 cases with posterior cleft palate), 38,151 population controls without any defects and 20,868 patient controls with other isolated defects were compared in the population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities (HCCSCA), 1980-1996.

Results: The proportion of professionals and managerials was lower, while the proportion of unskilled workers, housewives and others was higher in the mothers of cases with OFC compared with the population control group.

Increasing total prevalence rate of cases with Down syndrome in Hungary.

Recently the population-based large data set of the Hungarian Congenital Abnormality Registry showed an increase in the recorded total (birth + fetal) prevalence rate of informative offspring with Down syndrome. This finding was checked and confirmed in the completed data set due to the field study including all cytogenetic labs and prenatal diagnostic centres. The previous birth prevalence of 1.