Inherited genes

Disease Mode of Inheritance Gene Location Gene Product... 

O Differential effects of a drug - in vivo - in different patients, dependent on the presence of inherited gene variants... 

There must be ample information on the molecular genetic nature of the disorder (mode of inheritance, gene frequency, polymorphic nature of the locus, genetic heterogeneity of the disorder). 

JJ MacKay, DM O Malley, T Presnell, FL Booker, MM Campbell, RW Whetten, RR Sederoff. Inheritance, Gene Expression and Lignin Characterization in a Mutant Pine Deficient in Cinnamyl Alcohol Dehydrogenase. Proc Natl Acad Sci USA 94 8255, 1997. 

Bottom line At the present time in the United States, the consensus is that autism is a consequence of a development diversion that occurs before birth. In about i percent of cases there s evidence that the diversion is already programmed by inherited genes, but there s no evidence for complete genetic determinism of the disorder in 99 percent of cases. 

Neurodevelopmental models of schizophrenia have for the most part emphasized prenatal brain development, focusing on effects that may alter gene expression.15 For example, according to one idea, individuals with schizophrenia inherit genes that cause structural brain deviations that may be compounded by early environmental impact.16 Much of the focus of this hypothesis has been on postnatal impact, such as stress, that changes brain chemistry, but the idea can also accommodate a focus on prenatal impact. 

People who promote the idea that differences in IQ reflect differences in inherited genes usually also promote the idea that IQ differences are based on differences in the size of the brain. But there is absolutely no evidence that the total size of the adult brain is of primary importance in intelligence. 

The most important fundamental problem is that human twin studies of IQ heritability are too crude to generate meaningful quantitative results.16 And the qualitative results that are generated do not unequivocally demonstrate that IQ is determined primarily by inherited genes, although many newspaper and magazine articles declare just the opposite, with studies of twins often waved as proof of genetic determinism. 

Children inherit genes associated with cultural values that enhance survival but also genes that result in aggressive and competitive behavior. Instincts for killing others have had survival value over thousands of years. European countries have been engaged in warfare during 47% of those years (Sorokin, 1957). 

When one pair of chromosomes does not divide, the resulting cells have 24 chromosomes and others have 22. A fertilized egg will develop into a child with Down syndrome, where the child inherits genes on 46 chromosomes 23 coming from the mother and 23 from the father. The extra chromosome causes physical and cognitive abnormalities, ranging from mild-to-severe learning disabilities. The symptoms are similar to those of patients with Alzheimer s disease. 

The question of exactly how frequent gene defects of this type are involved in immune deficiency disease is not entirely answered. In most families studied the parents were not informative and similar gene defects could not be ruled in or out. Recently a second case has been encountered which is still under study. It would appear that these mechanisms are involved in immune deficiency but they are probably not a major cause. Another inherited gene defect encountered in families of some of these patients involves lower levels of specific genetic markers The role of these genes in immune deficiency remains unclear. A control gene defect has been postulated. It now appears more likely that the bulk of cases of immune deficiency involve other mechanisms and relate more directly to the lymphocyte. 

Le Corre, V. et al., Colonization with long-distance seed dispersal and genetic structure of maternally inherited genes in forest trees a simulation study. Genet. Res. Comb., 69, 117, 1997. 

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