what is the rate of concordance for schizophrenia in identical twins course hero

by Kristofer Brekke 9 min read

When discussing schizophrenia twin studies psychia- trists often report a 45%-50% concordance rate for identical twins, compared to only a 15% concordance rate for fraternal twins.

What is the rate of concordance for schizophrenia in identical twins?

[2] Analyzing classic studies of the genetics of schizophrenia done as early as in 1930s, Fischer concludes that a concordance rate for psychosis of about 50% in monozygotic twins seems to be a realistic estimate, which is significantly higher than that in dizygotic twins of about 10–19%.

What does concordance rate in twins mean?

Concordance, as used in genetics, usually means the presence of the same trait in both members of a pair of twins. However, the strict definition is the probability that a pair of individuals will both have a certain characteristic, given that one of the pair has the characteristic.

When concordance rates are higher among monozygotic twins than dizygotic twins This indicates which of the following group of answer choices?

Terms in this set (6) The higher the concordance rate, the more similar pairs of persons are within a sample. When concordance rates are higher among MZ than DZ twins, this indicates that the basis for the trait is partly genetic.

Why do identical twins have higher concordance rate?

Since MZ twins are genetically identical, as compared with DZ twins who only share, on average, half of their genomes, a greater concordance rate, that is, a greater phenotypic similarity, in MZ twins than in DZ twins is likely due to greater genetic similarity.

How is concordance rate calculated?

The concordance rate is the number of subjects that are concordant over the total number of subjects assessed. As can be seen in Figure 1, the concordance rate is calculated by adding the diagonal counts and dividing by the total number of subjects assessed.

What's a concordance rate?

the percentage of pairs of twins or other blood relatives who exhibit a particular trait or disorder.

What is the difference between monozygotic and dizygotic twins?

To form identical or monozygotic twins, one fertilised egg (ovum) splits and develops into two babies with exactly the same genetic information. To form fraternal or dizygotic twins, two eggs (ova) are fertilised by two sperm and produce two genetically unique children.

What's the difference between monozygotic MZ twins and dizygotic DZ twins?

MZ twins develop when one egg is fertilised by a single sperm and during the first two weeks after conception, the developing embryo splits into two. As a result, two, genetically identical babies develop. DZ twins occur when two eggs are released at a single ovulation and are fertilised by two different sperm.

What is the concordance for monozygotic and dizygotic twin respectively?

Monozygotic and dizygotic twin concordances are approximately 85% and 50%, respectively, for reading, and 70% and 50% for mathematics.

What does high concordance rate mean?

con·cor·dance rate A high rate of concordance may be generated in several ways, many of which may result from irrelevant bias; but broadly it is taken as evidence of causal connection (for example, in the case of identical twins, a genetic component or in spouses of assortative mating).

Which of the following disorders has the highest concordance rate for identical twins?

Bipolar disorder has a strong genetic component with high monozygotic twin concordance and estimates of heritability from population-based twin samples reported as high as 93% (Kieseppa, Partonen, Haukka, Kaprio, & Lonnqvist, 2004).

How do you calculate twin concordance?

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