Proposed Models
Twin and family studies show that autism is a highly heritable condition, but they have left many questions for researchers, most notably
- Why is fraternal twin concordance so low considering that identical twin concordance is high?
- Why are parents of autistic children typically non-autistic?
- Which factors could be involved in the failure to find a 100% concordance in identical twins?
- Is profound mental retardation a characteristic of the genotype or something totally independent?
Some researchers have speculated that what we currently refer to as "autism" may be a catch-all description for many yet unknown conditions with different genetic and/or environmental etiologies. This would appear to make the effort to find a genotype model a lot more difficult, and perhaps even pointless. Nevertheless, a number of genetic models have been proposed to try to explain the results of twin and sibling studies.
Read more about this topic: Heritability Of Autism
Famous quotes containing the words proposed and/or models:
“To coöperate in the highest as well as the lowest sense, means to get our living together. I heard it proposed lately that two young men should travel together over the world, the one without money, earning his means as he went, before the mast and behind the plow, the other carrying a bill of exchange in his pocket. It was easy to see that they could not long be companions or coöperate, since one would not operate at all. They would part at the first interesting crisis in their adventures.”
—Henry David Thoreau (1817–1862)
“Grandparents can be role models about areas that may not be significant to young children directly but that can teach them about patience and courage when we are ill, or handicapped by problems of aging. Our attitudes toward retirement, marriage, recreation, even our feelings about death and dying may make much more of an impression than we realize.”
—Eda Le Shan (20th century)