India's Opportunities and Challenges in Establishing a Twin Registry: An Unexplored Human Resource for the World's Second-Most Populous Nation.

Nature and nurture have always been a prerogative of evolutionary biologists. The environment's role in shaping an organism's phenotype has always intrigued us. Since the inception of humankind, twinning has existed with an unsettled parley on the contribution of nature (i.e. genetics) versus nurture (i.e. environment), which can influence the phenotypes. The study of twins measures the genetic contribution and that of the environmental influence for a particular trait, acting as a catalyst, fine-tuning the phenotypic trajectories. This is further evident because a number of human diseases show a spectrum of clinical manifestations with the same underlying molecular aberration. As of now, there is no definite way to conclude just from the genomic data the severity of a disease or even to predict who will get affected. This greatly justifies initiating a twin registry for a country as diverse and populated as India. There is an unmet need to set up a nationwide database to carefully curate the information on twins, serving as a valuable biorepository to study their overall susceptibility to disease. Establishing a twin registry is of paramount importance to harness the wealth of human information related to the biomedical, anthropological, cultural, social and economic significance.

The 2021 Congress of the International Society for Twin Studies: Twin Research at the Cutting Edge/Twin Research: Maternal Bonding with Twins; Twins with Peters Anomaly; Selective Termination in Dichorionic Twin Pairs; Neuropsychological Function in Twins with Neurofibromatosis/News Reports: World's Most Premature Survivor - A Twin; Twins Confuse Giants' Baseball Fans; Malaysian Twins Switched at Birth; 'Biracial' Twins.

Selected highlights from the 2021 Congress of the International Society for Twin Studies are reviewed. The perspectives of a new graduate student member to the society are also included. Timely research covering issues related to maternal bonding with twins, twins with Peters anomaly, selective termination in dichorionic twin pairs and neuropsychological functioning in twins with neurofibromatosis is reviewed. The final part of this article includes interesting and informative media reports related to the world's most premature survivor who is a twin, identical male baseball players, Malaysian twins switched at birth and a pair of the so-called 'biracial' twins.

SARS-CoV-2 (COVID-19)-specific T cell and B cell responses in convalescent rheumatoid arthritis: Monozygotic twins pair case observation.

Rheumatoid arthritis (RA) patients present higher risk of SARS-CoV-2 infection (COVID-19), and proper management of the disease in this population requires a better understanding of how the immune system controls the virus. We analyzed the T cell and B cell phenotypes, and their repertoire in a pair of monozygotic twins with RA mismatched for COVID-19 infection. Twin- was not infected, while Twin+ was infected and effectively controlled the infection. We found no significant changes on the αß T cell composition, while γδ T cells and B cells presented considerable expansion of memory population in Twin+ and robust T/B cell responses to several SARS-CoV-2 peptides. T cell receptor ß/γ-chain and immunoglobulin heavy chain next-generation sequencing depicted a remarkable higher diversity in Twin+ compared with Twin-, despite no significant changes being found in variable/joining family usage. Repertoire overlap analyses showed that, although being identical twins, very few clones were shared between them, indicating that COVID-19 may lead to deep changes on the immune cell repertoire in RA patients. Altogether, our results indicate that RA patients may develop robust and persistent COVID-19-specific T/B cell responses; γδ T cells and B cells may play a key role in the management of COVID-19 in RA, and the infection may lead to a profound reshaping of immune cell receptor specificities.

[The covid-19 pandemic in Italy: the impact on social life and mental health]. / La pandemia da covid-19 in Italia: l'impatto sulla vita e la salute mentale.

INTRODUCTION: Italy, one of the first countries to be heavily hit by the spread of the new Coronavirus, has activated precautionary measures aimed at limiting its spread. This emergency situation may be cause of psychological distress in the general population. Therefore, the Italian Twins Registry has decided to carry out an epidemiological study to investigate the social and mental health impact of the covid-19 pandemic on Italian adults. METHODS: The study has a longitudinal design and is aimed at twins of all ages residing in Italy. An online questionnaire was administered to collect information on socio-economic and health status of the participants, as well as of the households during the lockdown, and on the impact of the pandemic on participants' lives. Levels and prevalence of symptoms of anxiety, stress and depression were measured using validated instruments, such as the STAI-6, IES-R and PHQ-9. This article shows the results of the first wave of the survey (June 2020). RESULTS: A total of 2589 twins participated in the study, with a mean age of 45 years (range 18-93 years). Covid-19's prevalence among respondents was less than 1% and about 13% of the subjects reported that, at least, one of the household's members had symptoms of covid-19. Sixty percent of the participants changed the place and way of working and a third of the sample had to completely suspend their work. About half of the sample showed symptoms of an anxiety disorder and about 10% of the subjects had symptoms of a probable post-traumatic stress or depressive disorder. Higher mean scores on the three assessment instruments were observed among women, subjects with a low level of education and those residing in the Southern of Italy. Anxiety symptoms decreased with age. CONCLUSION: The study shows that the pandemic has had important repercussions on the socio-economic condition and mental health of the Italian population and suggests that some individuals are more vulnerable than others.

Genetic Correlates of Psychological Responses to the COVID-19 Crisis in Young Adult Twins in Great Britain.

We investigated how the COVID-19 crisis and the extraordinary experience of lockdown affected young adults in England and Wales psychologically. One month after lockdown commenced (T2), we assessed 30 psychological and behavioural traits in more than 4000 twins in their mid-twenties and compared their responses to the same traits assessed in 2018 (T1). Mean changes from T1 to T2 were modest and inconsistent. Contrary to the hypothesis that major environmental changes related to COVID-19 would result in increased variance in psychological and behavioural traits, we found that the magnitude of individual differences did not change from T1 to T2. Twin analyses revealed that while genetic factors accounted for about half of the reliable variance at T1 and T2, they only accounted for ~ 15% of individual differences in change from T1 to T2, and that nonshared environmental factors played a major role in psychological and behavioural changes. Shared environmental influences had negligible impact on T1, T2 or T2 change. Genetic factors correlated on average .86 between T1 and T2 and accounted for over half of the phenotypic stability, as would be expected for a 2-year interval even without the major disruption of lockdown. We conclude that the first month of lockdown has not resulted in major psychological or attitudinal shifts in young adults, nor in major changes in the genetic and environmental origins of these traits. Genetic influences on the modest psychological and behavioural changes are likely to be the result of gene-environment correlation not interaction.

Self-Reported Symptoms of COVID-19, Including Symptoms Most Predictive of SARS-CoV-2 Infection, Are Heritable.

Susceptibility to infection such as SARS-CoV-2 may be influenced by host genotype. TwinsUK volunteers (n = 3261) completing the C-19 COVID-19 symptom tracker app allowed classical twin studies of COVID-19 symptoms, including predicted COVID-19, a symptom-based algorithm to predict true infection, derived from app users tested for SARS-CoV-2. We found heritability of 49% (32-64%) for delirium; 34% (20-47%) for diarrhea; 31% (8-52%) for fatigue; 19% (0-38%) for anosmia; 46% (31-60%) for skipped meals and 31% (11-48%) for predicted COVID-19. Heritability estimates were not affected by cohabiting or by social deprivation. The results suggest the importance of host genetics in the risk of clinical manifestations of COVID-19 and provide grounds for planning genome-wide association studies to establish specific genes involved in viral infectivity and the host immune response.

Increased placental expression of angiotensin-converting enzyme 2, the receptor of SARS-CoV-2, associated with hypoxia in twin anemia-polycythemia sequence (TAPS).

INTRODUCTION: Recent reports suggest SARS-CoV-2, the virus causing COVID-19, may be transmittable from pregnant mother to placenta and fetus, albeit rarely. The efficacy of vertical transmission of SARS-CoV-2 critically depends on the availability of its receptor, ACE2, in the placenta. In the present study, we tested the hypothesis that placental ACE2 expression is oxygenation-dependent by studying the expression of ACE2 and associated cell entry regulators in the monochorionic twin anemia-polycythemia (TAPS) placenta, a model of discordant placental oxygenation. METHODS: We performed a retrospective comparative immunohistochemical, immunofluorescence and Western blot analysis of ACE2, TMPRSS2 and Cathepsin B expression in anemic and polycythemic territories of TAPS placentas (N = 14). RESULTS: ACE2 protein levels were significantly higher in the anemic twin territories than in the corresponding polycythemic territories, associated with upregulation of the key ACE2-related cell entry regulators, TMPRSS2 and Cathepsin B, immunolocalized to villous trophoblastic and stromal cells. Cellular colocalization of ACE2 and TMPRSS2, suggestive of functionality of this cell entry axis, was demonstrated by double immunofluorescence studies. DISCUSSION: Placental hypoxia is associated with upregulation of ACE2 expression, concomitant with increased expression of its key cell entry proteases. ACE2-regulated placental functions, both infection- and non-infection related, may be highly oxygenation-dependent.

Fear and depression linked to COVID-19 exposure A study of adult twins during the COVID-19 pandemic.

Millions of people have been impacted by the novel coronavirus (COVID-19) pandemic worldwide. High infection rates and death tolls, combined with social distancing measures, may have unintended psychological consequences on individuals. The goal of this study was to examine the interrelations between COVID-19 exposure, fear of COVID-19, and depression among a community-based sample of adult twins. We further explored whether fear of COVID-19 mediated the association between COVID-19 exposure and depression. 732 same-sex adult twin pairs (78.1% MZ, 21.9% DZ) completed an online survey examining their feelings in May 2020. About one-fifth of the participants reported having any COVID-19 exposure. Most participants (>80%) were somewhat concerned about themselves or their household members being infected by COVID-19. The average depression level was relatively low (M = 0.9 out of 6). We found that COVID-19 exposure was related to increased fears of COVID-19 and depression, and that depressive feelings increased with fear of COVID-19. The correlation between COVID-19 exposure and depression was partially mediated by fear of COVID-19. However, these associations were confounded by familial influences. As society navigates through the pandemic, it is essential to implement public health strategies to help individuals cope with the concerns and fears about COVID-19.

COVID-19: Twin Research in Progress/Twin Research Reviews: Asthmatic and Nonasthmatic Twins; Stanford University Study of Anal Prints; Twin Mammals and COVID-19; Twin Delivery and the Three 'Rs'/Mixed Media: The Rainman Twins - The Film; Twins Irish Pub; Twins 'Covid and Corona'; Death of a Surgeon Who Separated Conjoined Twins; Twinco - Twin-Based Supply Company.

It is likely that genetic factors play a role in the susceptibility to, and recovery from, COVID-19. A survey of ongoing twin research could produce findings likely to help in the prevention and management of this pandemic. This survey is followed by a review of research comparing selected features of asthmatic and nonasthmatic twins, links between twin mammals and COVID-19, and relationships between twin delivery and the three 'Rs'. The final section of this article presents newsworthy twin-related items, some associated with COVID-19. They include a summary of the Rainman Twins film, a study of anal prints, the 'Twins' Irish pub, newborn twins 'Covid and Corona', the death of a surgeon who separated conjoined twins, and Twinco, a twin-based supply company.

COVID-19 Recurrent Varies with Different Combinatorial Medical Treatments Determined by Machine Learning Approaches (preprint)

Various medical treatments for COVID-19 are attempted. After patients are discharged, SARS-CoV-2 recurring cases are reported and the recurrence could profoundly impact patient healthcare and social economics. To date, no data on the effects of medical treatments on recurrence has been published. We analyzed the treatment data of combinations of ten different drugs for the recurring cases in a single medical center, Shenzhen, China. A total of 417 patients were considered and 414 of them were included in this study (3 deaths) with mild-to-critical COVID-19. Patients were treated by 10 different drug combinations and followed up for recurrence for 28 days quarantine after being discharged from the medical center between February and May, 2020. We applied the Synthetic Minority Oversampling Technique (SMOTE) to overcome the rare recurring events in certain age groups and performed Virtual Twins (VT) analysis facilitated by random forest regression for medical treatment-recurrence classification. Among those drug combinations, Methylprednisolone/Interferon/Lopinavir/Ritonavir/Arbidol led to the lowest recurring rate (0.133) as compared to the average recurring rate (0.203). For the younger group (age 20-27) or the older group (age 60-70), the optimal drug combinations are different, but the above combination is still the second best. For obese patients, the combination of Ribavirin/Interferon/Lopinavir/Ritonavir/Arbidol led to the lowest recurring rate for age group of 20-50, whereas the combination of Interferon/Lopinavir/Ritonavir/Arbidol led to lowest recurring rate for age group of 50-70. The insights into combinatorial therapy we provided here shed lights on the use of a combination of (biological and chemical) anti-virus therapy and/or anti-cytokine storm as a potentially effective therapeutic treatment for COVID-19.