Day 5: Genetic Analisis

The case included no family pedigree so we created one.

Each X and Y represents the chromosomes while M and m represent the dominant gene, which is normal, and the recessive gene (m) that is Menkes.

Since Rick was a male he was much more prone to suffering from this disease because, since it’s X-linked, he only needed to receive one affected chromosome to gain the disease. Women are less likely to get the disease because they need to receive two affected X to suffer it, and if they only receive one she can live normally and just be a carrier, like Martha. This is a mother to son relationship no one would ever want.

Analysis Questions:

1. The mode of inheritance of Menkes Syndrome is recessive sex linked X linked disease (generally passed from mother to offspring), son is more likely to be affected

2. Martha has a sister Emily who is thinking about starting a family. She wonders if she, too, could have a child with Menkes syndrome. The chances that Emily is also a carrier of Menkes syndrome is  50%. The chances that a son of hers would be affected, assuming that the boy’s father does not have the Menkes gene, is  50%.

3. Martha’s brother George is also concerned that he could father son with Menkes Syndrome. He and his wife Phyllis have two healthy daughters.  The chance that a son of theirs inherits Menkes Syndrome is None, if he had the disease he would be dead.

4. The characteristic hair of Menkes syndrome results from the inability of hair keratin to form disulfide (sulfur-sulfur) bridges. The two amino acids most likely to be affected are adenosine triphosphatase and tyrosinase.

5. The phenomenon responsible for the observation that Martha has some unusual hairs and some normal ones is one of X chromosomes contains the mutated gene locus , while the other does not.

6. An Australian physician, D. M. Danks, saw his first patient with Menkes syndrome at Johns Hopkins University in 1971. He noted the striking resemblance between the patient’s hair and that of sheep in his homeland that graze on copper-deficient soil. The sheep hair anomaly is a common symptom of Menkes Disease, which is also present in humans.