Part II – The Diagnosis Elise stared out the window of the bus at the rush-hour
ID: 3515225 • Letter: P
Question
Part II – The Diagnosis Elise stared out the window of the bus at the rush-hour traffi c that had befallen travelers on the other side of the highway. She recalled that night back in November when her mother called her at school to share the fateful news about her sister. “Shannon has been diagnosed with schizophrenia,” was what she had said. Th e words had dropped into the pit of Elise’s stomach. She had known that something was going wrong with her sister. Th e summer before she left for college, Elise noticed changes in Shannon’s behavior. Despite being an avid swimmer and lifeguard, Shannon quit her highly coveted swim camp instructor position just two weeks into the summer. She seemed withdrawn and unmotivated, and had also unexpectedly decided not to attend college in the fall, despite Elise’s and her parent’s eff orts to convince her otherwise. But Elise did not get to see the worst of Shannon’s behavior, when she began having hallucinations and couldn’t seem to carry on a coherent conversation with her parents. Elise had done some research about schizophrenia after hearing of her sister’s diagnosis. She did not like what she found out. Apparently, schizophrenia has a tendency to run in families. In fact, studies indicate that a sibling of a schizophrenic has a 10-fold higher risk of developing schizophrenia over the general population. Elise began to worry about her own mental health. She decided she would do some further investigation into the disease once she got home for summer break.
You are encouraged to use the review articles below to answer these questions. Please cite them in paragraph form when answering.
1. What causes genetic variation? For example, what causes some people to have curly hair and others to not? What causes some people to have a genetic disease such as cystic fi brosis and others to not?
2. What does it mean when a trait or a disease “runs in families”?
3. What could be some possible genetic and non-genetic causes of Shannon’s schizophrenia?
Review Articles Gejman, P.V., Sanders, A.R., and Kendler, K.S. (2011). Genetics of schizophrenia: new fi ndings and challenges. Th e Annual Review of Genomics and Human Genetics 12: 121–44. Roth, T.L., Lubin, F.D., Sodhi, M., and Kleinman, J.E. (2009). Epigenetic mechanisms in schizophrenia. Biochim Biophys Acta 1790(9): 869–877. Rutten, B.P. and Mill, J. (2009). Epigenetic mediation of environmental infl uences in major psychotic disorders. Schizophrenia Bulletin 35(6): 1045–1056.
Explanation / Answer
1.Genetic variation is the variations in the DNA sequence in the genomes.Genetic variations are caused by mutations ,random mating ,random fertization, crossing over .
Reshuffling of alleles takes place which gives offspring a different combination from parents .Moreover man and women produce different gametes so numerous variations in chromosomes exist.Alleles in any of possible form in which a gene for particular trait can occur, these are found in triplets in some genes. Difference in triplets in a person possess unusual characters than his siblings e.g red hair curly hair .cystic fibrosis is also a genetic disorder .
2.In such a condition it is clear that the trait is inheritable which is passed from parents to offsprings and so on. They may be caused by gene mutations which are inherited.
3) Possible Genetic causes of Schzophrenea
Genetic cause for schizophrenia accounts for almost 80% of a person's risk to get this disease .it may be caused by genetic changes or mutations .Shannon may be a carrier for genetic factors that increase the chances of Schzophrenea. Genes like GADI ,5-HTZA ,COMT ARE RESPONISUBLE .
DYSBINDIN ,NEUREGULIN 1 , PROLINE FEHYDROGENAESE too are reasons.
ENVIRINMENTAL CAUSES
it was found that viral infections like influenza before the birth of offspring have more chances of getting Schzophrenea. It means when offspring is in womb the mother suffers from infections it will lead to Schzophrenea in offspring .
Certain drugs like methamphetamines or LSD are also a cause for it.
Thanks