GENETIC

DISEASES

Student’s Copy

GENOME EXHIBITION

Dexter Tan (Mr)/ 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:

YES

NO

Hector Gee (Mr)/ 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)

Germaine Poh (Ms)/ 14 Years Old

Diagnosis

What is the disease Germaine is suffering from? (GN-09)

Cystic Fibrosis Down’s Syndrome Breast CancerMuscular 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?

BRCA1 APOE e4 CFTRBRCA2

(ii) How did Germaine get a mutation in the gene?

ChemotherapyChemotherapy 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 parents

Exposure 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?