Genetics and Diseases Quiz

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Questions and Answers

Which chromosome is associated with candidate regions for schizophrenia?

Chromosome 1

Chromosome 15

Chromosome 14

Chromosome 22 (correct)

What gene is associated with catecholamine synthesis in affective diseases?

Tyrosine hydroxylase gene (correct)

Angiotensinogen gene

Insulin gene

Rhinine gene

What is the most common cause of dementia cases in individuals over 65 years of age?

Parkinson's disease

Vascular dementia

Alzheimer's disease (correct)

Frontotemporal dementia

What is a genetic factor involved in hypertension?

Angiotensinogen gene (D) Signup and view all the answers

Which condition is characterized by mutations in different genes related to sarcoma proteins?

Familial hypertrophic cardiomyopathy (B) Signup and view all the answers

In coronary heart disease, which factor is NOT identified as a pathogenetic mechanism?

Venous blood return issues (D) Signup and view all the answers

How does Alzheimer's disease progress in terms of clinical symptoms?

Progresses from 4 to 12 years (B) Signup and view all the answers

What inheritance pattern is associated with familial hypertrophic cardiomyopathy?

Autosomal dominant inheritance (C) Signup and view all the answers

What is a common clinical feature associated with Turner syndrome?

Short stature (A), Normal intellect (C) Signup and view all the answers

Which chromosomal composition is associated with Turner syndrome?

45, X (A) Signup and view all the answers

Which of the following is a potential dental issue associated with certain chromosomal diseases?

Increased tooth loss risk (C) Signup and view all the answers

What condition features a female phenotype with a male karyotype, specifically a mutation in the testosterone receptor?

Morris syndrome (D) Signup and view all the answers

Inherited chromosomal diseases can be classified according to which of the following principles?

Time of occurrence of mutations (C) Signup and view all the answers

What is a notable feature of Down syndrome?

Leading cause of congenital heart disease (A) Signup and view all the answers

What is the population frequency for Turner syndrome?

1 in 2500 live births (C) Signup and view all the answers

What distinguishes the full form from the mosaic form of chromosomal diseases?

Type of mutation in the child (B) Signup and view all the answers

When do full chromosomal aberrations typically occur?

During gametogenesis (B) Signup and view all the answers

How does the clinical manifestation of Polysomy X change with the number of X chromosomes?

Increases with more chromosomes (C) Signup and view all the answers

What is the frequency range of Down syndrome occurrence?

1 in 900 to 1 in 700 live births (B) Signup and view all the answers

Which factor affects the genetic risk of chromosomal diseases in the family?

Age of the mother (A) Signup and view all the answers

Which characteristic is typical of mosaic chromosomal diseases?

Only some cells have the chromosomal aberration (B) Signup and view all the answers

Which statement best describes genomic imprinting?

Only one allele is expressed regardless of sex (A) Signup and view all the answers

Which of the following is a type of chromosomal aberration that may lead to chromosomal diseases?

Trisomy (D) Signup and view all the answers

Numerical chromosomal aberrations can include which of the following?

Monosomy (C) Signup and view all the answers

What can be said about the genetic component in polygenic diseases?

It arises from multiple mutant genes. (B) Signup and view all the answers

Which of the following diseases is characterized by a multifactorial basis where genetic and exogenous factors intertwine?

Schizophrenia (A) Signup and view all the answers

What distinction exists between the risk of schizophrenia in first-degree relatives compared to the general population?

It is higher than the general population's risk. (B) Signup and view all the answers

Which of the following genes is NOT considered a candidate gene for schizophrenia?

Insulin receptor gene (D) Signup and view all the answers

How does the frequency of schizophrenia in monozygotic twins compare to dizygotic twins?

It is higher in monozygotic twins. (C) Signup and view all the answers

What is the role of dopamine in relation to Parkinson's disease?

It is important for neurotransmitter activity affected in Parkinson's disease. (C) Signup and view all the answers

Which statement best describes the inheritance pattern of schizophrenia?

It does not have a specific type of inheritance. (C) Signup and view all the answers

What unique recognition did Arvid Carlson receive for his work related to dopamine?

The Nobel Prize in Medicine and Physiology (D) Signup and view all the answers

What is a common physical characteristic associated with Prader-Willi Syndrome?

Small scrotum (C) Signup and view all the answers

Which genetic alteration is most frequently associated with Angelman Syndrome?

Deletion on chromosome 15 (D) Signup and view all the answers

Which of the following is a symptom of Williams Syndrome?

Hoarseness (A) Signup and view all the answers

What type of behavioral issue is commonly observed in individuals with Prader-Willi Syndrome?

Behavioral problems (B) Signup and view all the answers

What is a potential cause of cardiovascular disease in individuals with Williams Syndrome?

Insufficient elastin production (C) Signup and view all the answers

Which syndrome is characterized by severe absence in physical development and hypopigmentation?

Prader-Willi Syndrome (B) Signup and view all the answers

What type of chromosomal alteration is most often found in Angelman Syndrome?

Structural aberration of the maternal chromosome (B) Signup and view all the answers

What percentage of Angelman Syndrome cases result from maternal chromosome deletion?

70% (A) Signup and view all the answers

What is the most common cause of Partial monosomy 18q-?

Daytime mutation in gametogenesis (C) Signup and view all the answers

Which symptom is NOT associated with Patau syndrome?

Cat-like crying (D) Signup and view all the answers

What is a common symptom of Cri-du-chat syndrome?

Specific crying similar to a cat (D) Signup and view all the answers

What chromosomal alteration leads to Wolf-Hirschhorn syndrome?

Deletion in the distal part of chromosome 4 (A) Signup and view all the answers

What is the frequency of Patau syndrome in live births?

1:12000 - 1:8000 (A) Signup and view all the answers

Which of the following is a common physical characteristic of patients with Cri-du-chat syndrome?

Flat nose (D) Signup and view all the answers

What is the typical outcome for children born with Patau syndrome?

They rarely live beyond one year of age (D) Signup and view all the answers

Syndrome Wolf-Hirschhorn can arise from what type of chromosomal alteration?

A newly formed defect or inherited deletion (B) Signup and view all the answers

Study Notes

Polygenic Diseases

Multifactorial diseases result from complex interactions of genetic and exogenous factors at various levels.
The genetic component can involve a single gene predisposing to a multifactorial disease, a few mutated genes causing oligogenic disease, or numerous mutated genes in polygenic diseases.
Examples include schizophrenia, affective disorders, Alzheimer's disease, hypertension, coronary heart disease, familial hypertrophic cardiomyopathy, and bronchial asthma.

Schizophrenia

Multifactorial with intertwined genetic and exogenous factors.
Familial risk is higher in first-generation (10%) and second-generation (3%).
Adopted children's frequency is higher in those related to the sick person.
Frequency higher in monozygotic than dizygotic twins.
Doesn't follow Mendelian inheritance.
Candidate genes include dopamine receptor, dopamine transporter, amyloid precursor, glutamate receptor, tyrosine dehydrogenase, serotonin receptor, and 5-hydroxytryptamine receptor genes.
Dopamine (3,4-dihydroxy-β-phenylethylamine) is a catecholamine. It functions as a neurotransmitter, produced by neurons in substantia nigra, and leads to norepinephrine and epinephrine.
Candidate regions are on chromosome 22 (Xp21, Xq11.2-q12, 15q21, 15q23-q24, 21q22.1-q22.2, DXYS1 locus).

Affective Diseases

Multifactorial, divided into manic-depressive (bipolar), psychosis, and depressive psychoses.
Associated with the candidate gene for tyrosine hydroxylase.
Alternative splicing produces four different mRNAs with protein synthesis differences in brain regions.
Localized to chromosome 11 adjacent to the insulin gene.

Alzheimer's Disease

The most common cause of dementia in adults over 65 (60-80% of cases).
Clinically characterized by senile dementia, progressing for 4-12 years, ending in death.
Inheritance can be AD in some families, and not specified in others.
Down syndrome patients display Alzheimer's-typical brain changes.
Genes associated are located on chromosome 21, 14, and 1.

Hypertension

Multifactorial disease involving both genetic and exogenous factors.
Candidate genes include the rhinine gene, angiotensinogen gene, and genes functioning in the endothelium.

Coronary Heart Disease

Underlying pathogenetic mechanisms related to lipoprotein transport, metabolism, or structure in cholesterol, hypertension, thrombogenesis, thrombolysis, fibrinolysis, impaired blood flow due to atherosclerotic plaques, and regulatory/congenital anomalies.

Familial Hypertrophic Cardiomyopathy

Polygenic and heterogeneous.
Caused by mutations in various genes.
Genetic products are sarcoma proteins.
Characterized by asymptomatic forms, syncope, myocardial ischemia, heart failure, and sudden death—most common cardiac cause of death under 35.
Genetic risk is 50% for offspring in AD inheritance—children may have a more severe clinical picture than parents.

Bronchial Asthma

Common heterogeneous disease in childhood.
Allergic/atopic type is the most common, characterized by IgE reaction to inhaled protein allergens.
Often accompanies familial accumulation of allergic manifestations like seasonal rhinitis and childhood eczema.
Over 20 candidate genes have been identified.

Diseases Associated with Somatic Mutations

Somatic cell mutations disrupt DNA structure and function at a rate of 10⁻⁶ per gene/cell.
Mutations are usually not phenotypically significant, but under specific conditions, such as dividing embryonic cells, they can lead to cellular proliferation forming faster-growing cancer clones.
Chromosomal mosaicism involves post-zygotic mutations resulting in multiple genetically distinct cell lines.
Gonadal mosaicism includes healthy parents with children with AD (autosomal dominant) disease.

Chromosomal Diseases (Etiology and Classification)

Caused by chromosomal mutations impacting chromosome numbers or structure (structural aberrations).
Clinical symptoms arise from changes in hereditary material (surplus or loss).
Classification: inherited/non-inherited chromosomal diseases, full/polar forms based on mutation occurrence time, and chromosomal aberrations located on autosomes or sex chromosomes.
Includes monosomy and trisomy

Peculiarities of Inherited Chromosomal Diseases

First Case: Normal karyotype in parents; full form—numerical chromosomal aberration.
Second Case: Normal karyotype in parents; mosaic form—either numerical or unbalanced structural chromosomal aberration.
Mutation Timing: gametogenesis or embryogenesis.
Disease Manifestations: vary based on mutation time and location, as well as maternal/parental age.
Recurrence Risk: depends on the mother's age in some chromosomal diseases.

Differences Between Full and Mosaic Forms of Chromosomal Diseases

Full Form: Normal parent karyotype, all cells share chromosomal aberration; full clinical manifestation.
Mosaic Form: Normal parent karyotype, only some cells have chromosomal aberration; partial clinical manifestation.

Genomic Imprinting

Sex-linked expression of only one allele (maternal or paternal) of a single genetic locus.
Gene activity relies on cytosine methylation in CG-rich gene regulatory regions.
Genes are active in hypomethylation and inactive in hypermethylation.
Genetic imprinting involves methylation of one allele within the allelic pair, determining parental inheritance characteristics.

Chromosomal Diseases in Structural or Numerical Aberrations of Sex Chromosomes:

Klinefelter syndrome (47, XXY): Due to an extra X chromosome, affecting males; common symptoms include hypogonadism (reduced testes), infertility & possible gynecomastia, & tall stature.
Superman syndrome (47, XYY): Presents with extra Y chromosome, with no significant specific symptoms.
46, XX in males: Shows phenotypic abnormalities like short stature.
Turner syndrome (45, X): Results from missing/partially missing X chromosome in females. Common symptoms include short stature, ovarian dysgenesis (failure of the ovaries), and other somatic abnormalities.
Polysomy X (47, XXX; 48, XXXX; 49, XXXXX): Multiple X chromosomes, with increasing symptoms as the number of X chromosomes rises. Examples include hypertelorism, and possible cognitive delays.
Morris syndrome (46, XY): Genetically male presenting with female phenotype. A mutation of the TFM testosterone receptor gene.

Chromosomal Diseases in Structural or Numerical Aberrations of Autosomes:

Down syndrome (Trisomy 21): Caused by an extra copy of chromosome 21. Symptoms include mental retardation, congenital heart disease, facial features, and physical characteristics.
Edwards syndrome (Trisomy 18): Caused by an extra copy of chromosome 18. Presentation includes severe mental and physical abnormalities, and high chance of early death.
Cri du Chat syndrome (5p-): Deletion of part of chromosome 5. Symptoms include infant cry that sounds like a cat's meow, microcephaly, low birth weight & muscular hypotonia.
Patau syndrome (Trisomy 13): An extra 13th chromosome. Symptoms include severe facial abnormalities, major organ defects, and high infant mortality.
Partial monosomy 18q-: Deletion in chromosome 18, displaying mental issues, facial features and other severe symptoms.
Prader-Willi syndrome: Microdeletion on chromosome 15, and presents with unique characteristics. Examples include mental retardation, physical disabilities and unique appearance.
Angelman syndrome: Microdeletion on chromosome 15 (maternal), and presents with unique characteristics. Examples include absence of psychomotor development, behavioral issues, and cognitive abnormalities.
Williams syndrome: Deletion on the 7th chromosome, presenting with unique characteristics like facial traits and potentially cardiovascular or connective tissue-related issues.

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Test your knowledge on the genetic factors and conditions associated with various diseases in this informative quiz. Explore questions on schizophrenia, dementia, and other affective disorders. Perfect for students and professionals in the fields of genetics and medicine.