G ENETIC D ISEASES Student’s Copy GENOME EXHIBITION

D exter T an ( M r)/ 4 Years Old/ Learning Disabilities Cause What is the cause of the disease? Point Mutation (GN-15) Chromosomal Number Change (GN-38) Genetic Engineering (GN-37) Diagnosis What is the disease Dexter is suffering from? (GN-09) Cystic Fibrosis Down’s Syndrome Breast Cancer Muscular Dystrophy Mr and Mrs Tan have a 4 year old boy, named Dexter, who is suffering from learning disabilities. Feeling that something is wrong with Dexter, Mr and Mrs Tan consult a general practitioner, and are in turn referred to you, a genetic counsellor. Mrs Tan is carrying a second child and is eager to know if the unborn child may suffer from the same disease. You need to select an appropriate technique for Mrs Tan to go through to allay her anxiety. Genetic Screening (i) Which method is preferred? Pre-natal Screening/ Karyotype (GN-19) Microarray (GN-22) Gene Sequencing (GN-21) DNA Profiling (GN-35) (ii) Why is this method preferred? A genetic diagram is often constructed by a genetic counsellor to predict the chances of a newborn baby having a certain genetic disease Genetic Diagram Do you think you could construct a genetic diagram for the Tans to explain how Dexter has his disorder? If yes, construct the genetic diagram at the back. If no, write down your reason below: YESNO

H ector Gee ( M r)/ 6 Years Old/ Loss of Muscular Function Cause What is the cause of the disease? Mutation (GN-15) Chromosomal Number Change (GN-38) Genetic Engineering (GN-37) Diagnosis What is the disease Hector is suffering from? (GN-09) Cystic Fibrosis Down’s Syndrome Breast Cancer Muscular Dystrophy Mrs Gee has a boy named Hector. By the time Hector was six years old, something was amiss. Hector suffered from loss of muscular function in his lower limbs and required braces to move around. Mrs Gee consulted a general practitioner about Hector, and was in turn referred to you, a genetic counsellor for advice. The government decided to offer some help with the treatment for Hector. Treatment What kinds of treatment are currently available for someone born with genetic diseases? (GN-24; GN-39; GN-41; GN-25)

G ermaine P oh ( Ms )/ 14 Years Old Diagnosis What is the disease Germaine is suffering from? (GN-09) Cystic Fibrosis Down’s Syndrome Breast Cancer Muscular Dystrophy Germaine Poh is a 14 year old Secondary student recently diagnosed with breast cancer. She is very concerned about her condition. Thus, she has come to you, the genetic counsellor, for a consultation to find out why she is suffering from breast cancer at such a young age. It was determined that the breast cancer that Germaine is suffering is due to a mutation in a specific gene. Cause (i) Which of the following genes could be mutated to cause breast cancer? BRCA1APOE e4CFTRBRCA2 (ii) How did Germaine get a mutation in the gene? Chemotherapy Chemotherapy can be used to cure certain breast cancer patients. However, a certain type of genetic screening has to be carried out to find out whether the patient is suitable for the treatment. Genetic Screening (i) Which type of genetic screening is used to find out the suitability of treatment? GALT Inherited from parentsExposure to carcinogens (cancer-causing agents) Consumption of genetically modified organisms Pre-natal Screening/ Karyotyping (GN-19) Microarray (GN-22) Gene Sequencing (GN-21) DNA Profiling (GN-35) (ii) Why is this method preferred?