MODULE 2 Adrenoleukodystrophy
Go to website http://www.ncbi.nlm.nih.gov/ This is the homepage for the National Center for Biotechnology Information. It serves as a portal to many other databases.
On the right side of the screen, under “Hot Spots”, click on “Genes and Diseases”. Your screen should now have a picture of the 24 human chromosomes (22 autosomes and 2 sex chromosomes) and a list of many diseases. Notice that the list is divided into categories. Under “Glands and Hormones” click on Adrenoleukodystrophy .
What happens in this disease?
On the left side of the screen, in the “Links” section, are a series of websites with additional information on ALD. Click on the “Fact Sheet” in the website section.
What are the symptoms of early-onset ALD?
What treatments are available?
What is the prognosis?
Now click on “Genome View”.
How many chromosomes play a role in ALD inheritance? __________________
Which chromosome has the most hits? ________________
Go back to the ALD page and click on “Entrez Gene”.
What gene type is involved in ALD? _______________
What is the gene name? _____________________
What do ABC proteins do? _________________________________________________
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On the top of the ALD page, click on the chromosome number that had the most hits. On your screen is a picture of the chromosome with the mutation that causes ALD.
How many genes are on this chromosome? _______________
How many total diseases are coded for on this chromosome _______________
What are they? __________________________________________________________
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Which disease is located closest to the gene for ALD? ___________________
Click on this disease,
Who is mostly affected by this disease? ______________________
Who is a carrier? ______________________
How does this compare to the people suffering from ALD? ____________________
Click on the “DMD” gene.
Who is mostly affected by this disease? ___________________________
Can you think of why diseases located on this chromosome seem to affect specific people?
MODULE 2 TEACHER KEY
OMIM Module – Adrenoleukodystrophy
What happens in this disease? _____________________ (In this disease, the fatty covering (myelin sheath) on nerve fibers in the brain is lost, and the adrenal gland degenerates, leading to progressive neurological disability and death.)
On the left side of the screen, in the “Links” section, are a series of websites with additional information on ALD. Click on the “Fact Sheet” in the website section.
What are the symptoms of early-onset ALD?
The most common symptoms are usually behavioral changes such as abnormal withdrawal or aggression, poor memory, and poor school performance. Other symptoms include visual loss, learning disabilities, seizures, poorly articulated speech, difficulty swallowing, deafness, disturbances of gait and coordination, fatigue, intermittent vomiting, increased skin pigmentation, and progressive dementia
What treatments are available?
Adrenal function must be tested periodically in all patients with ALD. Treatment with adrenal hormones can be lifesaving. Symptomatic and supportive treatments for ALD include physical therapy, psychological support, and special education. Recent evidence suggests that a mixture of oleic acid and euric acid, known as "Lorenzo's Oil," administered to boys with X-ALD can reduce or delay the appearance of symptoms. Bone marrow transplants can provide long-term benefit to boys who have early evidence of X-ALD, but the procedure carries risk of mortality and morbidity and is not recommended for those whose symptoms are already severe or who have the adult-onset or neonatal forms. Oral administration of docosahexanoic acid (DHA) may help infants and children with neonatal ALD.
What is the prognosis?
Prognosis for patients with ALD is generally poor due to progressive neurological deterioration. Death usually occurs within 1 to 10 years after the onset of symptoms.
Now click on “Genome View”.
How many chromosomes play a role in ALD inheritance? __________________ (7)
Which chromosome has the most hits? ________________ (X)
Go back to the ALD page and click on “Entrez Gene”.
What gene type is involved in ALD? _______________ (protein coding)
What is the gene name? ______________________ (ABCD1)
What do ABC proteins do? _____________________ (ABC proteins transport various molecules across extra- and intra-cellular membranes.)
On the top of the ALD page, click on the chromosome number that had the most hits. On your screen is a picture of the chromosome with the mutation that causes ALD.
How many genes are on this chromosome? _______________ (1400)
How many total diseases are coded for on this chromosome _______________(11)
What are they? ______________ (Duchenne Muscular Dystrophy, PIG-A, Menkes Syndrome, Alport Syndrome, Immunodeficiency, Hemophilia, Rett Syndrome, Fragile X Syndrome, Lesch Nyhan Syndrome, X-linked SCID, ALD)
Which disease is located closest to the gene for ALD? ___________ (hemophilia)
Click on this disease, who is mostly affected by this disease? __________ (males)
Who is a carrier? __________ (females)
How does this compare to the people suffering from ALD? ___________ (same)
Click on the “DMD” gene. Who is mostly affected by this disease? _______ (male)
Can you think of why diseases located on this chromosome seem to affect specific people? _____________________ (X-linked diseases are carried by females, who have two copies of the X chromosome, while males only have 1 copy, and are susceptible to the many disorders)