Genetics of Schizophrenia

The Genetics of Schizophrenia: Article Review
Schizophrenia has long been acknowledged as one of the most notoriously heritable of all mental health disorders. As noted by Mukherjee (2016) in his New Yorker article, “Runs in the Family: New Findings About Schizophrenia Rekindle Old Questions About Genes and Identity,” even before the heritability of certain characteristics through genes was well understood, the fact that schizophrenia ran in families had been noted. The first individual to define schizophrenia in a medical context, Eugen Bleuler, distinguished how young people, usually in their late teens or early twenties, began to experience visions, paranoid delusions, and the ability to express their thoughts in a continuous fashion. They often experienced extreme shifts between emotional shifts as well. A common linking element was that patients often had close relatives with similar symptoms. This was true of his own family, Mukherjee admitted.
Twin studies later confirmed Bleuler’s suspicions. Having an identical twin increased the chances of developing the disorder as much as 50% and there was also a strong association with being diagnosed with bipolar disorder as well (which was also manifested in Mukherjee’s family). But what makes schizophrenia so challenging to study is that there is no single gene or single bullet associated with the disorder. In fact, many genes are associated with schizophrenia. But what is most perplexing is that some individuals inherit the entire constellation of risk genes and never develop the disorder, even those with disordered identical twins. This suggests that epigenetics, or the interaction between genes and the environment, are responsible for stimulating the disorder.
Today, it is far easier to track genetic patterns and heritability than it was when the disorder was first identified. A 2006 international study of 3,322 patients and 3,587 controls, involving 7,000 genomes found more than a hundred segments associated with the disorder. The most promising and unusual finding was a gene segment on chromosome 6 known as the MHC region and is typically associated with the immune system. Scientists were particularly interested in the inheritance of two specific genes; the more C4A protein a particular gene variant produced, the greater the likelihood of developing schizophrenia. Other promising findings include research into the role of cells known as the microglia which have a significant role in eliminating extraneous brain synapses. Significantly, it is in adolescence when the most pruning is needed, and that is also when schizophrenia often strikes.
Scientists now theorize that an abundance of C4 protein can cause too much synaptic pruning, thus generating the symptoms of schizophrenia. But this is a description of the process, not necessarily a plan to prevent the illness, since the reasons certain individuals with the gene have issues with synaptic pruning and others do not remains unclear. Once again, there must be an interaction between environment and genetics. Mukherjee also notes that this may partially explain the association between madness and creativity, which he also noted in his own family. Irregular synaptic pruning may cause unusual creative associations and enable leaps of logic to occur, those “aha” moments of problem-solving of highly creative people.
As yet, it is still uncertain how to translate this knowledge about C4 proteins into treatment. At best, only the symptoms of schizophrenia are contained by current medications and therapies. The disease itself cannot be eradicated, although some sufferers do get better over time and there is a continuum of functionality of sufferers of the disorder. Still, many patients must remain institutionalized so scientists still continue to look for a cure for an illness which has shortened the careers and stunted the personal lives of many sufferers.



References
Mukherjee, S. (2016). Runs in the family: new findings about schizophrenia rekindle old
questions about genes and identity. The New Yorker. 92(7), 26.