The Process of Family Reconstruction after DNA Testing for Huntington Disease

The needs of families to reconstruct their relationships in response to the DNA testing for Huntington disease of one or more of their asymptomatic members are presented. Data were collected from family interviews with 18 families, and from their responses on a post interview questionnaire. Findings are that families need to (a) address unfinished business associated with the decision for testing; (b) bring family members, peripheral in the decision for testing, into the loop; (c) reorganize patterns of communication and roles altered by the testing and heal ruptures in family membership; and (d) revise family stories about illness to provide a meaning for HD and explain the test results in a way that leaves them with a sense of mastery. Findings suggest that families should be more involved in the initial decision for testing of a member and that protocols should be established to provide help for their ongoing adjustment.     

Genetic Counseling for Fragile X Syndrome: Updated Recommendations of the National Society of Genetic Counselors

These recommendations describe the minimum standard criteria for genetic counseling and testing of individuals and families with fragile X syndrome, as well as carriers and potential carriers of a fragile X mutation. The original guidelines (published in 2000) have been revised, replacing a stratified pre- and full mutation model of fragile X syndrome with one based on a continuum of gene effects across the full spectrum of FMR1 CGG trinucleotide repeat expansion. This document reviews the molecular genetics of fragile X syndrome, clinical phenotype (including the spectrum of premature ovarian failure and fragile X-associated tremor-ataxia syndrome), indications for genetic testing and interpretation of results, risks of transmission, family planning options, psychosocial issues, and references for professional and patient resources. These recommendations are the opinions of a multicenter working group of genetic counselors with expertise in fragile X syndrome genetic counseling, and they are based on clinical experience, review of pertinent English language articles, and reports of expert committees. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. The professional judgment of a health care provider, familiar with the facts and circumstances of a specific case, will always supersede these recommendations.     

Constrained maximum likelihood estimation of two-level covariance structure model via EM type algorithms

In this paper, the constrained maximum likelihood estimation of a two-level covariance structure model with unbalanced designs is considered. The two-level model is reformulated as a single-level model by treating the group level latent random vectors as hypothetical missing-data. Then, the popular EM algorithm is extended to obtain the constrained maximum likelihood estimates. For general nonlinear constraints, the multiplier method is used at theM-step to find the constrained minimum of the conditional expectation. An accelerated EM gradient procedure is derived to handle linear constraints. The empirical performance of the proposed EM type algorithms is illustrated by some artifical and real examples.This research was supported by a Hong Kong UCG Earmarked Grant, CUHK 4026/97H. We are greatly indebted to D.E. Morisky and J.A. Stein for the use of their AIDS data in our example. We also thank the Editor, two anonymous reviewers, W.Y. Poon and H.T. Zhu for constructive suggestions and comments in improving the paper. The assistance of Michael K.H. Leung and Esther L.S. Tam is gratefully acknowledged.     

A medical records managing and securing blockchain based system supported by a Genetic Algorithm and Discrete Wavelet Transform

The privacy of patients is jeopardised when medical records and data are spread or shared beyond the protected cloud of institutions. This is because breaches force them to the brink that they start abstaining from full disclosure of their condition. This type of condition has a negative effect on scientific research, patients and all stakeholders. A blockchain-based data sharing system is proposed to tackle this issue, which employs immutability and autonomy properties of the blockchain to sufficiently resolve challenges associated with access control and handle sensitive data. Our proposed system is supported by a Discrete Wavelet Transform to enhance the overall security, and a Genetic Algorithm technique to optimise the queuing optimization technique as well. Introducing this cryptographic key generator enhances the immunity and system access control, which allows verifying users securely in a fast way. This design allows further accountability since all users involved are already known and the blockchain records a log of their actions. Only when the users’ cryptographic keys and identities are confirmed, the system allows requesting data from the shared queuing requests. The achieved execution time per node, confirmation time per node and robust index for block number of 0.19 s, 0.17 s and 20 respectively that based on system evaluation illustrates that our system is robust, efficient, immune and scalable.     

Fitting direct covariance structures by the MSTRUCT modeling language of the CALIS procedure

This paper demonstrates the usefulness and flexibility of the general structural equation modelling (SEM) approach to fitting direct covariance patterns or structures (as opposed to fitting implied covariance structures from functional relationships among variables). In particular, the MSTRUCT modelling language (or syntax) of the CALIS procedure (SAS/STAT version 9.22 or later: SAS Institute, 2010) is used to illustrate the SEM approach. The MSTRUCT modelling language supports a direct covariance pattern specification of each covariance element. It also supports the input of additional independent and dependent parameters. Model tests, fit statistics, estimates, and their standard errors are then produced under the general SEM framework. By using numerical and computational examples, the following tests of basic covariance patterns are illustrated: sphericity, compound symmetry, and multiple‐group covariance patterns. Specification and testing of two complex correlation structures, the circumplex pattern and the composite direct product models with or without composite errors and scales, are also illustrated by the MSTRUCT syntax. It is concluded that the SEM approach offers a general and flexible modelling of direct covariance and correlation patterns. In conjunction with the use of SAS macros, the MSTRUCT syntax provides an easy‐to‐use interface for specifying and fitting complex covariance and correlation structures, even when the number of variables or parameters becomes large.     

Socio-cultural selection and the sculpting of the human genome: Cultures’ directional forces on evolution and development

This paper argues for culture as a significant determinant of the modern human genome. As progress in the fields of genetics and evolutionary biology have gained greater insights into evolutionary process, aspects of classical proposals explaining how phenotypic responses to environmental experience could make their way into the genotype have returned in new guises. Recent proposals recognize environmental context as a key source of genetic variation by directly altering selection pressures to mask and unmask adaptive value of expressed traits, by reorganizing the combination and expression of genes during ontogeny to provide novel variants for selection, and by influencing developmental trajectories through epigenetic systems acutely sensitive to ontogenetic contexts. The emergence of a robust human socio-cultural niche, shielding humans from more proximate evolutionary pressures that marked our ancestral evolution, has arguably provided the strongest directive force on modern human evolution. Language is discussed as an exemplar of a cultural niche with a powerful self-organizing dynamic and the potential to dramatically alter the human genome.     

Impact of genetic testing on causal models of heart disease and arthritis: An analogue study

Abstract

An analogue study investigated the impact of genetic testing on perceptions of disease. Using a 2 × 2 design, participants (n = 212) imagined receiving the information that they were at increased risk for either heart disease or arthritis. The type of risk information was either genetic or unspecified. Presentation of genetic risk information resulted in the condition being perceived as less preventable. Causal models of disease where investigated using principal components analysis. When hem disease was the stimulus condition, attributions to genes and chance were positively associated following unspecified risk information, and negatively associated following genetic risk information. When arthritis was the stimulus condition, presentation of genetic risk information was associated with attributions to genes becoming separated from the other attributions. One explanation for this is that providing genetic risk information may decrease perceptions of a sense of randomness or uncertainty in disease causation. The extent to which these effects occur in clinical populations. and their behavioural consequences. needs to be established.     

Illness perceptions and distress in women at increased risk of breast cancer

Variation in the levels of distress in women at increased risk of breast cancer has been reported, yet there is limited understanding of the factors that are associated with heightened distress in this population. This study took a theoretical approach using Leventhal's Self Regulatory Model (SRM) to understand variation in distress levels. The study examined the associations between perceptions of breast cancer and distress in women at increased risk of breast cancer, and a comparison sample with no experience of the disease in their social environment. Questionnaire data from 117 women at increased risk of breast cancer and 100 comparison women were analysed. Women at increased risk of breast cancer showed comparable levels of general distress but significantly higher levels of cancer specific distress than the comparison group. There were few differences in illness perceptions between the samples, although a number of cognitive perceptions of breast cancer were related to both general and cancer specific distress in the increased risk sample, but not in the comparison sample. The results suggest that the SRM provides a useful framework to explore the psychological response to genetic risk. Further research is required in this population to examine illness perceptions in more detail, validate quantitative measures of illness perceptions, and examine interactions between risk perception and the SRM constructs.     

Developing Standard Recommendations (Guidelines) for Genetic Counseling Practice: A Process of the National Society of Genetic Counselors

The National Society of Genetic Counselors (NSGC) supports the development of practice recommendations (guidelines) in the field of genetic counseling. This paper reviews the basic components of NSGC genetic counseling practice recommendations as well as the process for formal adoption of such documents, as approved by the Board of Directors of the NSGC.     

Who's controlling whom? Infant contributions to maternal play behavior

Because the way mothers play with their children may have significant impacts on children's social, cognitive, and linguistic development, researchers have become interested in potential predictors of maternal play. In the present study, 40 mother–infant dyads were followed from child age 5–20 months. Five‐month habituation rate and 13 and 20 month temperamental difficulty were found to be predictive of maternal play quality at 20 months. The most parsimonious theoretical model was one in which habituation was mediated by temperamental difficulty in predicting mother play. Consistent with prior speculation in the literature, these data support the possibility that mothers adjust some aspects of their play behaviors to fit their children's cognitive and temperamental capabilities. Copyright © 2003 John Wiley & Sons, Ltd.