Non-Infectious Diseases caused by Genes

Objectives At the end of the lesson, students will be able to:  State how genetically-linked diseases are caused  Describe the characteristics of some genetically-linked diseases  List some examples of genetically-linked diseases.  Displaying a positive attitude towards people in society who suffer with genetically-linked diseases.

Causes of Genetically-Linked Diseases  Abnormal genes of the person with the disease  The defective genes may be inherited from one or both parents, that is, the disease is hereditary.

Causes of Genetically- Linked Diseases Cont’d  In some cases, the genes may not be inherited, the person with the disease could have a genetic disorder

Examples of Genetically-linked diseases Down’s Syndrome  A genetic disorder caused by the body’s cells having three copies of chromosome 21, instead of the usual two copies

Down’s Syndrome Cont’d  The extra genetic material in the extra chromosome disrupts the normal development of a child.

Characteristics of Down’s Syndrome  Flat facial profile  Upwards slanting eyes  A short neck

Characteristics of Down’s Syndrome Cont’d  Abnormally shaped ears  White spot on the iris of the eyes

Short video

Haemophilia  A Hereditary blood disorder which usually only affects males.  Females may possess the gene responsible for the disease, but they are generally unaffected.

Haemophilia Cont’d  Such females are said to be carriers of the gene, and may pass the condition to their male children.

Haemophilia Cont’d  Genetic disorders like haemophilia which only affect one gender or sex, are said to be sex- linked conditions.

Activity#1 for Haemophilia  Read the following passage carefully and see if you can come up with the characteristics for Haemophilia  A 15 years old girl comes to the clinic with complain of heavy menses (periods). She also complain sometimes she had nose bleed and easy bruising. She had previous surgical history of tonsillectomy at age 6 years, which required blood transfusion for excessive bleeding. Her mother required a hysterectomy after giving birth to her younger brother because of excessive haemorrhage.

Characteristics of Haemophilia  Delayed clotting in the blood  Uncontrolled bleeding, even with minor injuries  Easy bruising

Cystic Fibrosis  Caused by mutation in a certain gene.  An inherited disease of the mucus glands, in which abnormally think and sticky mucous is produced in the body’s organs.

 This leads to damage in the respiratory system.  Cystic Fibrosis affects the digestive system as well because mucous can block the ducts of the pancreas and prevents digesting food.

Sickle- Cell Anaemia  Caused by a mutated gene which produces defective Haemoglobin, the protein that enables red blood cells to carry oxygen.

Sickle- Cell Anaemia Cont’d  The sickle-shaped red blood cells are destroyed rapidly by the body causing anaemia ( Low number of red blood cells in the blood).

Sickle- Cell Anaemia Cont’d  Anaemia leads to shortness of breath, fatigue and delayed growth and development in children.  This inherited disorder can lead to infection and episodes of pain.

 Some other diseases, like hypertension, diabetes mellitus and some types of cancer, may be genetically linked, as they often run in families, although they may also be caused by other factors.

HOME - WORK  Create an awareness brochure (2 pages, sizes of pages 8.5’’*14’’) using Microsoft Office & Google Images on the causes and characteristics of genetically-linked diseases ( what we did in class today) and state some positive ways society should treat people who suffer with them. (Do additional research on the internet for more information).