Regarding the genetics of schizophrenia, which of the following is correct?
ExplanationSchizophrenia (discussed also in questions 24 and 25) is not thought to be a monogenic disorder; its genetics are thought to be more complex than simple Mendelian disorders, and it is not 1100 transmitted in an autosomal dominant fashion. Schizophrenia aggregates in families, and the results of epidemiologic studies, twin studies, adoption studies, and genetic linkage and association studies suggest that schizophrenia is a genetic disorder, with phenotypic expression of the disorder being influenced by a variety of environmental factors. The concordance rate (the rate of twins that are each affected) for schizophrenia is higher among monozygotic compared to dizygotic twins. Several schizophrenia susceptibility loci have been mapped to various chromosomes, with candidate genes including dysbindin on chromosome 6 and neuregulin-1 on chromosome 8. Other genetic abnormalities detected in schizophrenia include chromosomal deletions, trinucleotide repeat expansions, and copy number variants. Evidence from genome-wide association studies have identified several potential single-nucleotide polymorphisms that may be significantly associated with risk of schizophrenia, including polymorphisms in dopamine receptor genes.
