Describe the inheritance and expression of cystic fibrosis, Tay-Sachs disease and sickle-cell anemia.
I didn't understand what the question meant by "expression." Please help!
Thank you for using the Jiskha Homework Help Forum. When you encounter a word, don't forget a good dictionary where you can look for the various meanings:
Main Entry: ex·pres·sion
Pronunciation: ik-'spre-sh&n
Function: noun
Date: 15th century
1 a : an act, process, or instance of representing in a medium (as words) : UTTERANCE <freedom of expression> b (1) : something that manifests, embodies, or symbolizes something else <this gift is an expression of my admiration for you> (2) : a significant word or phrase (3) : a mathematical or logical symbol or a meaningful combination of symbols (4) : the detectable effect of a gene; also : EXPRESSIVITY 1
2 a : a mode, means, or use of significant representation or symbolism; especially : felicitous or vivid indication or depiction of mood or sentiment <read the poem with expression> b (1) : the quality or fact of being expressive (2) : facial aspect or vocal intonation as indicative of feeling
3 : an act or product of pressing out
- ex·pres·sion·al /-'spresh-n&l, -'spre-sh&-n&l/ adjective
In other words, how is manifested, shown?
When discussing genetic disorders such as cystic fibrosis, Tay-Sachs disease, and sickle-cell anemia, the term "expression" refers to how these disorders occur in individuals at a clinical level. In other words, it refers to the signs, symptoms, and severity with which these disorders manifest in affected individuals.
Now, let's dive into the inheritance patterns and expression of each disorder:
1. Cystic Fibrosis:
Inheritance: Cystic fibrosis (CF) follows an autosomal recessive inheritance pattern. This means that a person must inherit two copies of the defective CF gene (one from each parent) to develop the condition.
Expression: Individuals with CF experience abnormalities in their exocrine glands, particularly in the respiratory and digestive systems. The thick mucus produced by these glands can obstruct airways, leading to difficulty breathing. Digestive complications also arise due to blocked pancreatic ducts, impairing the breakdown and absorption of nutrients. Typical symptoms include chronic cough, recurrent lung infections, poor growth, and malnutrition.
2. Tay-Sachs Disease:
Inheritance: Tay-Sachs disease is inherited in an autosomal recessive manner. This means that an individual must inherit two copies of the faulty Tay-Sachs gene to develop the disease.
Expression: Tay-Sachs disease is a neurodegenerative disorder that affects the central nervous system. It typically manifests in infancy, causing progressive deterioration of motor and mental skills. Affected children may experience seizures, loss of muscle tone, and vision and hearing problems. Unfortunately, there is currently no cure for this disease.
3. Sickle-Cell Anemia:
Inheritance: Sickle-cell anemia is inherited in an autosomal recessive manner. It occurs when an individual receives two copies of the abnormal hemoglobin gene, one from each parent.
Expression: Sickle-cell anemia is a hereditary blood disorder where red blood cells become misshapen, resembling a sickle. This abnormal shape causes the cells to become stiff, sticky, and block blood flow, leading to pain, fatigue, anemia, organ damage, and increased vulnerability to infections. The severity of symptoms can vary widely between individuals. Interestingly, having sickle-cell trait (inheriting a single copy of the abnormal gene) can provide some protection against malaria, making it more prevalent in certain regions where malaria is common.
Understanding the inheritance patterns and phenotypic expressions of genetic disorders is crucial for genetic counseling, diagnosis, and support for individuals and families affected by these conditions.