Genetics - Diseases and Disorders

1. Hereditary Diseases Huntington's, Cystic Fibrosis

Some diseases are not caused by problems during cell division, but are thought to have specific genes (or damage to genes) that cause or trigger them.  These genes are present in the parents and are passed down to the children. In this way we say that they are inherited.  These types of diseases run in families.

Genes that code for traits can come in two different forms (alleles).They can either be dominant or recessive.  You receive one allele for each gene from your mom and one from your father.  If you receive two dominant alleles for a trait from your parents, you will have that trait.  If the gene is for a disease, you will have that disease.  

An example of a dominant genetic disease is Huntington's.  Quite a lot is known about the genes involved and we are able to test individuals to see if they have the gene marker.  However, if one of your parents has this gene, you have a 50% chance of getting it passed on to you, and developing the disease.  In the case of this disease you only need to receive the trait from one parent, because the trait is Dominant. 

Recessive genetic diseases can be passed along from generation to generation, but because an individual needs to get the recessive allele from both of the parents, the disease does not show up in them. Examples are cystic fibrosis, albinism, phenylketonuria, galactosemia, and Tay-Sachs disease.  Look at this website to read more about a disease you may be interested in.

Most genetic traits or diseases, however are not caused by a single gene. Remember, some traits appear to be caused by a single gene, but most other traits are caused with a combination of many genes, and environmental factors.

2. Schizophrenia - a Hereditary Genetic Link?

As we have discussed in previous topics, the exact cause of psychological disorders is often not well understood, although is it a well researched and debated field in psychology and neuroscience.  Recent studies have shown that disorders such as schizophrenia  appear to be in some way hereditable, as it does appear to run in families.  Some researchers have been studying the genes of people with this disease to determine if it has an underlying genetic cause.

Although some researchers are studying the possible genetic link to this disorder, others still do not agree.

In the following video, adoption studies ( which will be discussed in the next book) show a familiar link to schizophrenia.  

3. Autism- A Heritable Genetic Link?

Another disorder, Autism, is now thought to have some genetic link.

4. Do Genetics Determine Who we are?

We have introduced the ideas of genetics in this book, but do our genes control who we are? 

Are genes alone responsible for physical characteristics as well as behavioural and emotional characteristics?  The ideas behind this debate continue today, and have important implications for us as people.  If we are genetically predisposed to having a bad temper, being irresponsible, uptight, or being happy go lucky? Are we stuck with those traits, or can we change?

The next book will look at the ideas of our genes, and our environment and which one has a greater influence on us as humans.