Principles of Genetics Assignment 1

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Questions and Answers

What is the primary cause of Maturity-Onset Diabetes of the Young (MODY)?

Insulin resistance in muscle cells

Obesity-related hormonal imbalances

Mutation in a single gene (correct)

Autoimmune destruction of beta cells

Which gene is associated with HNF1A-MODY?

HNF4A gene

HNF1B gene

GCK gene

HNF1A gene (correct)

What is the function of the protein produced from the GCK gene?

Increases insulin receptor sensitivity in tissues

Promotes insulin production in liver cells

Facilitates glucose uptake in the intestines

Acts as a glucose sensor and stimulates insulin release (correct)

How do mutations in the HNF1A, HNF4A, or HNF1B genes affect insulin production?

Produce dysfunctional transcription factors that impair insulin production Signup and view all the answers

Which of the following describes the inheritance pattern of MODY?

Autosomal dominant inheritance with one mutated copy sufficient Signup and view all the answers

What complication is associated with mutations in the HNF1B gene?

Kidney developmental abnormalities Signup and view all the answers

What is the typical percentage of MODY cases attributed to HNF1B mutations?

Less than 5% Signup and view all the answers

What role do the proteins produced from the MODY-related genes primarily have?

Acting as transcription factors regulating gene activity Signup and view all the answers

What is the primary cause of monogenic diabetes like MODY?

Single gene mutation Signup and view all the answers

Which of the following genes is commonly associated with MODY?

HNF1A Signup and view all the answers

How does the inheritance pattern of monogenic diabetes like MODY differ from polygenic diabetes?

Monogenic diabetes follows a Mendelian pattern Signup and view all the answers

Approximately what percentage of MODY cases are attributed to mutations in the HNF1A gene?

30% to 60% Signup and view all the answers

What distinguishes MODY from other types of diabetes?

It results from mutations in a single gene Signup and view all the answers

Which of the following statements accurately reflects the nature of polygenic diabetes?

Environmental factors contribute to its development Signup and view all the answers

How many different known MODY mutations currently exist?

At least 14 Signup and view all the answers

What role does Mendelian inheritance play in the prediction of diabetes inheritance?

It is critical for understanding family lineage in monogenic types Signup and view all the answers

What is the inheritance pattern of MODY?

Autosomal dominant Signup and view all the answers

Which test is typically the first step in diagnosing MODY?

Blood sugar test Signup and view all the answers

What blood glucose level range indicates the need for lifestyle changes in a potential MODY patient?

100 to 125 mg/dL Signup and view all the answers

Why is it essential to measure C-peptide in diagnosing diabetes types?

To assess endogenous insulin production Signup and view all the answers

What fasting blood glucose level range is considered normal?

70 mg/dL to 100 mg/dL Signup and view all the answers

What characteristic is typically observed in patients with MODY2?

Stable mild fasting hyperglycemia Signup and view all the answers

What is a challenge associated with measuring C-peptide levels?

Samples must be centrifuged and frozen quickly Signup and view all the answers

Which biochemical technique is non-invasive but requires good patient compliance?

24-h urinary C-peptide collection Signup and view all the answers

Study Notes

College of Health Sciences

Principles of Genetics
Assignment No. 1

Group Members

A list of student names and their unique student identification numbers (UGR) is provided.

Submission Date

15/11/24

Introduction
- What are genetic disorders?
- What are the causes of genetic mutation?
- Classification of genetic disorders
- Tests for genetic disorders
- Treatment and Prevention of genetic disorders
Literature review on how Mendelian principles are applicable to diagnose human disease
- The role of Mendelian inheritance in diagnosing genetic disease
- Monogenic disorders and Mendelian inheritance
- Mendel's Principles for genetic inheritance helped us identify genes for Mendelian disorders
- Diagnosis of Genetic disease
- Genetic Testing
- How to apply Mendelian genetics to diagnose Diabetes Mellitus
- Application of Mendelian Genetics in diagnosing diabetes mellitus
- What is Diabetes?
- Mendel's law and MODY inheritance
- Biochemical techniques to diagnose MODY
- Conclusion
- Ethical consideration of testing genes (diabetes mellitus)
- Recommendations
- Reference

Introduction

Gregor Mendel's experiments with peas are the foundation of modern genetics.
Mendel's work, initially unrecognized, was later recognized as foundational.
His work focused on how traits are inherited, leading to three postulates:
- Unit factors in pairs
- Dominance and recessiveness
- Segregation
Genetic disorders arise from mutations in genes or chromosomes; these are often hereditary.
Mutations can be caused by natural or external factors.

Classification of Genetic Disorders

Single-gene disorders (unifactorial)
- Caused by mutations in a single gene.
- Inheritance pattern is predictable.
- Categorized based on whether the trait is sex-specific (X-linked) or not.
Autosomal disorders (dominant / recessive)
- Dominant: affected individuals are heterozygous.
- Recessive: individuals need two copies of the mutated gene.
X-linked disorders (dominant / recessive)
- More females affected in X-linked dominant conditions.
- Males are more likely to be affected in X-linked recessive conditions.

Chromosomal Disorders

Numerical (aneuploidy)
- Caused by an abnormal number of chromosomes (e.g., trisomy, monosomy)
Structural
- Deletion: loss of a portion of a chromosome.
- Duplication: extra copy of a portion of a chromosome
- Inversion: broken and rejoined portion of chromosome
- Translocation: transfer of chromosome segments to other chromosomes

Multifactorial Genetic Disorders

Caused by gene mutations and other factors (e.g., chemical exposure, alcohol)

Diagnosis of Genetic Disorders

Methods include physical examination, family history, and genetic testing.
Cytogenetic, Biochemical, and molecular testing.

Genetic Testing

Cytogenetic testing
- Examines whole chromosomes for abnormalities under a microscope.
Biochemical testing
- Tests protein activity, level of metabolites, and the size of proteins.
Molecular testing
- Analyzes small DNA mutations by direct DNA testing.

How to apply Mendelian genetics to diagnose Diabetes Mellitus

Diabetes Mellitus is a chronic disorder characterized by high blood glucose levels.
MODY (Maturity-onset diabetes of the young) is a monogenic form of diabetes.
Genes involved in MODY (e.g., HNF1A, HNF4A, GCK) follow Mendelian inheritance patterns.

Biochemical Techniques in Diagnosing MODY

C-peptide
- Measures amount of endogenous insulin.
Blood test
- Measures blood glucose levels;
High-sensitivity C-reactive protein (hsCRP) testing is a biochemical marker and may help distinguish between certain MODY types.

Conclusion

Mendelian genetics is crucial in understanding and diagnosing genetic diseases, including diabetes.
Genetic testing helps identify the role of different genes in genetic disorders
Considering ethical implications is also essential when dealing with genetic disorders

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Description

This quiz covers key concepts in genetic disorders and the application of Mendelian principles in diagnosing human diseases. It includes discussions on genetic mutation causes, classification, and prevention measures. Explore the literature on the role of Mendelian inheritance and its relevance to conditions such as Diabetes Mellitus.