The Experts below are selected from a list of 2268 Experts worldwide ranked by ideXlab platform
R Lew - One of the best experts on this subject based on the ideXlab platform.
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Discontinuity and quasi‐continuity: Alternative hypotheses of Multifactorial Inheritance
Clinical Genetics, 2008Co-Authors: Newton E. Morton, S Yee, R. C. Elston, R LewAbstract:Consequences of three models of Multifactorial Inheritance are deduced for inbreeding effects and recurrence risks, and methods are developed to test goodness of fit. Applying the computer program DISQUAC to several bodies of data, we find that every one which fits a quasi-continuous modcl also fits a discontinuous one. Our results show that it is exceedingly difficult, and may be practically impossible, to infer the genetic basis of traits which do not give regular mendelian ratios. The only consolation is that predicted recurrence risks are esscntially the same for similar models. Thus the two quasi-continuous models of Falconer and Edwards, which assume cumulative gene action, seem in practice indistinguishable, while the genetic load model can be differentiated only if there is significant dominancc. Useful predictions for genetic counseling may be made from a well-fitting model even when the mode of Inheritance is unclear. In particular, it is shown how to estimate the probability of affection in the next child after s sibs have been born, of whom r were affected, when there is no birth order effect.
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discontinuity and quasi continuity alternative hypotheses of Multifactorial Inheritance
Clinical Genetics, 2008Co-Authors: N E Morton, S Yee, R. C. Elston, R LewAbstract:Consequences of three models of Multifactorial Inheritance are deduced for inbreeding effects and recurrence risks, and methods are developed to test goodness of fit. Applying the computer program DISQUAC to several bodies of data, we find that every one which fits a quasi-continuous modcl also fits a discontinuous one. Our results show that it is exceedingly difficult, and may be practically impossible, to infer the genetic basis of traits which do not give regular mendelian ratios. The only consolation is that predicted recurrence risks are esscntially the same for similar models. Thus the two quasi-continuous models of Falconer and Edwards, which assume cumulative gene action, seem in practice indistinguishable, while the genetic load model can be differentiated only if there is significant dominancc. Useful predictions for genetic counseling may be made from a well-fitting model even when the mode of Inheritance is unclear. In particular, it is shown how to estimate the probability of affection in the next child after s sibs have been born, of whom r were affected, when there is no birth order effect.
F. C. Fraser - One of the best experts on this subject based on the ideXlab platform.
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Multifactorial Inheritance of non‐syndromic macrocephaly
Clinical Genetics, 2008Co-Authors: Laura Arbour, Gordon V. Watters, Judith G. Hall, F. C. FraserAbstract:Objective To reevaluate previous claims that non-syndromic macrocephaly is usually inherited as an autosomal dominant trait. Design Head size was measured in the parents and sibs of children with non-syndromic macrocephaly. Outcome measures If autosomal dominant Inheritance is involved, the frequency distribution should be bimodal. Results Head circumference of parents and sibs of the macrocephalic probands had a mean significantly greater than the population norm, and a unimodal distribution. Probands with psychomotor impairment had bigger heads, and more had a history of birth difficulty, than did unimpaired probands. Conclusions The usual genetic basis for non-syndromic macrocephaly is Multifactorial with a polygenic genetic basis, rather than autosomal dominant. Risk of recurrence appears to be much lower than if it would be on the assumption of autosomal dominant Inheritance. Macrocephaly in a parent or sib of an unborn child may present a risk for birth injury to that child. A larger series of patients will be necessary to resolve this question.
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Multifactorial Inheritance of non syndromic macrocephaly
Clinical Genetics, 2008Co-Authors: Laura Arbour, Gordon V. Watters, Judith G. Hall, F. C. FraserAbstract:Objective To reevaluate previous claims that non-syndromic macrocephaly is usually inherited as an autosomal dominant trait. Design Head size was measured in the parents and sibs of children with non-syndromic macrocephaly. Outcome measures If autosomal dominant Inheritance is involved, the frequency distribution should be bimodal. Results Head circumference of parents and sibs of the macrocephalic probands had a mean significantly greater than the population norm, and a unimodal distribution. Probands with psychomotor impairment had bigger heads, and more had a history of birth difficulty, than did unimpaired probands. Conclusions The usual genetic basis for non-syndromic macrocephaly is Multifactorial with a polygenic genetic basis, rather than autosomal dominant. Risk of recurrence appears to be much lower than if it would be on the assumption of autosomal dominant Inheritance. Macrocephaly in a parent or sib of an unborn child may present a risk for birth injury to that child. A larger series of patients will be necessary to resolve this question.
R. C. Elston - One of the best experts on this subject based on the ideXlab platform.
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Discontinuity and quasi‐continuity: Alternative hypotheses of Multifactorial Inheritance
Clinical Genetics, 2008Co-Authors: Newton E. Morton, S Yee, R. C. Elston, R LewAbstract:Consequences of three models of Multifactorial Inheritance are deduced for inbreeding effects and recurrence risks, and methods are developed to test goodness of fit. Applying the computer program DISQUAC to several bodies of data, we find that every one which fits a quasi-continuous modcl also fits a discontinuous one. Our results show that it is exceedingly difficult, and may be practically impossible, to infer the genetic basis of traits which do not give regular mendelian ratios. The only consolation is that predicted recurrence risks are esscntially the same for similar models. Thus the two quasi-continuous models of Falconer and Edwards, which assume cumulative gene action, seem in practice indistinguishable, while the genetic load model can be differentiated only if there is significant dominancc. Useful predictions for genetic counseling may be made from a well-fitting model even when the mode of Inheritance is unclear. In particular, it is shown how to estimate the probability of affection in the next child after s sibs have been born, of whom r were affected, when there is no birth order effect.
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discontinuity and quasi continuity alternative hypotheses of Multifactorial Inheritance
Clinical Genetics, 2008Co-Authors: N E Morton, S Yee, R. C. Elston, R LewAbstract:Consequences of three models of Multifactorial Inheritance are deduced for inbreeding effects and recurrence risks, and methods are developed to test goodness of fit. Applying the computer program DISQUAC to several bodies of data, we find that every one which fits a quasi-continuous modcl also fits a discontinuous one. Our results show that it is exceedingly difficult, and may be practically impossible, to infer the genetic basis of traits which do not give regular mendelian ratios. The only consolation is that predicted recurrence risks are esscntially the same for similar models. Thus the two quasi-continuous models of Falconer and Edwards, which assume cumulative gene action, seem in practice indistinguishable, while the genetic load model can be differentiated only if there is significant dominancc. Useful predictions for genetic counseling may be made from a well-fitting model even when the mode of Inheritance is unclear. In particular, it is shown how to estimate the probability of affection in the next child after s sibs have been born, of whom r were affected, when there is no birth order effect.
S Yee - One of the best experts on this subject based on the ideXlab platform.
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Discontinuity and quasi‐continuity: Alternative hypotheses of Multifactorial Inheritance
Clinical Genetics, 2008Co-Authors: Newton E. Morton, S Yee, R. C. Elston, R LewAbstract:Consequences of three models of Multifactorial Inheritance are deduced for inbreeding effects and recurrence risks, and methods are developed to test goodness of fit. Applying the computer program DISQUAC to several bodies of data, we find that every one which fits a quasi-continuous modcl also fits a discontinuous one. Our results show that it is exceedingly difficult, and may be practically impossible, to infer the genetic basis of traits which do not give regular mendelian ratios. The only consolation is that predicted recurrence risks are esscntially the same for similar models. Thus the two quasi-continuous models of Falconer and Edwards, which assume cumulative gene action, seem in practice indistinguishable, while the genetic load model can be differentiated only if there is significant dominancc. Useful predictions for genetic counseling may be made from a well-fitting model even when the mode of Inheritance is unclear. In particular, it is shown how to estimate the probability of affection in the next child after s sibs have been born, of whom r were affected, when there is no birth order effect.
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discontinuity and quasi continuity alternative hypotheses of Multifactorial Inheritance
Clinical Genetics, 2008Co-Authors: N E Morton, S Yee, R. C. Elston, R LewAbstract:Consequences of three models of Multifactorial Inheritance are deduced for inbreeding effects and recurrence risks, and methods are developed to test goodness of fit. Applying the computer program DISQUAC to several bodies of data, we find that every one which fits a quasi-continuous modcl also fits a discontinuous one. Our results show that it is exceedingly difficult, and may be practically impossible, to infer the genetic basis of traits which do not give regular mendelian ratios. The only consolation is that predicted recurrence risks are esscntially the same for similar models. Thus the two quasi-continuous models of Falconer and Edwards, which assume cumulative gene action, seem in practice indistinguishable, while the genetic load model can be differentiated only if there is significant dominancc. Useful predictions for genetic counseling may be made from a well-fitting model even when the mode of Inheritance is unclear. In particular, it is shown how to estimate the probability of affection in the next child after s sibs have been born, of whom r were affected, when there is no birth order effect.
Laura Arbour - One of the best experts on this subject based on the ideXlab platform.
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Multifactorial Inheritance of non‐syndromic macrocephaly
Clinical Genetics, 2008Co-Authors: Laura Arbour, Gordon V. Watters, Judith G. Hall, F. C. FraserAbstract:Objective To reevaluate previous claims that non-syndromic macrocephaly is usually inherited as an autosomal dominant trait. Design Head size was measured in the parents and sibs of children with non-syndromic macrocephaly. Outcome measures If autosomal dominant Inheritance is involved, the frequency distribution should be bimodal. Results Head circumference of parents and sibs of the macrocephalic probands had a mean significantly greater than the population norm, and a unimodal distribution. Probands with psychomotor impairment had bigger heads, and more had a history of birth difficulty, than did unimpaired probands. Conclusions The usual genetic basis for non-syndromic macrocephaly is Multifactorial with a polygenic genetic basis, rather than autosomal dominant. Risk of recurrence appears to be much lower than if it would be on the assumption of autosomal dominant Inheritance. Macrocephaly in a parent or sib of an unborn child may present a risk for birth injury to that child. A larger series of patients will be necessary to resolve this question.
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Multifactorial Inheritance of non syndromic macrocephaly
Clinical Genetics, 2008Co-Authors: Laura Arbour, Gordon V. Watters, Judith G. Hall, F. C. FraserAbstract:Objective To reevaluate previous claims that non-syndromic macrocephaly is usually inherited as an autosomal dominant trait. Design Head size was measured in the parents and sibs of children with non-syndromic macrocephaly. Outcome measures If autosomal dominant Inheritance is involved, the frequency distribution should be bimodal. Results Head circumference of parents and sibs of the macrocephalic probands had a mean significantly greater than the population norm, and a unimodal distribution. Probands with psychomotor impairment had bigger heads, and more had a history of birth difficulty, than did unimpaired probands. Conclusions The usual genetic basis for non-syndromic macrocephaly is Multifactorial with a polygenic genetic basis, rather than autosomal dominant. Risk of recurrence appears to be much lower than if it would be on the assumption of autosomal dominant Inheritance. Macrocephaly in a parent or sib of an unborn child may present a risk for birth injury to that child. A larger series of patients will be necessary to resolve this question.