Schizophrenia: genes matter (even though inheritance might not)

[n2doc]

By John Timmer | Published about 21 hours ago

A large number of human disorders—autism and cancer among them—display a confusing pattern of inheritance. In some cases, they are clearly genetic, with frequent occurrences in individual families. But in others, new cases will appear in families that were otherwise unaffected.

Initially, this pattern was assumed to result from diseases that had multiple causes. But with some diseases, we've come to recognize that mutations (whether inherited or not) play a much larger role than expected. The latest disease to join this category is schizophrenia.

Schizophrenia is a behavioral disorder that follows the pattern of many others, including autism and dyslexia: in many cases, it runs in families, and these families have allowed us to identify mutations in key genes that are associated with the disorder. In many other instances, however, only a single individual in a family is affected, which suggests that environmental causes may play a key role in these cases.

In recent years, an alternative explanation has been proposed: mutations are nearly always important for these diseases, but the mutations aren't always inherited. This first became clear for cancer, where researchers realized that sporadic cases of the disease resulted from mutations that cells had picked up over the course of their history in the body (and that environmental influences act by altering the frequency of mutations). There's generally a substantial overlap between these sporadic mutations and the ones that are mutated in the cancer's heritable form.

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http://arstechnica.com/science/news/2011/08/genetics-is-key-schizophrenia-even-when-inheritance-isnt.ars

[KT2000]

1. this is why

thorough testing of chemicals is so important. Sometimes they are tested for genetic damage and cancer but nothing else.
The chemicals we are exposed to have not been thoroughly tested. Many of them were grandfathered in and some had their testing done by a fraudulent lab so they were grandfathered in.