Topic 3. The role of the heredity, constitution, age-related changes in pathology.

Question 1

Give the types of diseases, depending on the role of the heredity and environment.

Answer 1

Infectious diseases, hereditary diseases, deficiency diseases and physiological diseases
We can also classify diseases as communicable and non-communicable

Question 2

What is a congenital disorder?

Answer 2

A congenital disorder is a condition that is present from birth. Congenital disorders can be inherited or caused by environmental factors.

Question 3

What are phenocopies?

Answer 3

Those diseases which are caused by environmental factors and have a clinical picture similar to known hereditary diseases, are call phenocopies.

Question 4

What are the three types of hereditary diseases?

Answer 4

Based on their genetic contribution, human diseases can be classified as monogenic, chromosomal, or multifactorial

Question 5

What are monogenetic diseases?

Answer 5

Monogenic diseases are caused by alterations in a single gene, and they segregate in families according to the traditional Mendelian principles of inheritance.

Question 6

What are chromosomal diseases?

Answer 6

Chromosomal diseases, as their name implies, are caused by alterations in chromosomes. For instance, within an individual’s genome, some chromosomes may be missing, extra chromosome copies may be present, or certain portions of chromosomes may be deleted or duplicated.

Question 7

What are multifactorial diseases (complex diseases)?

Answer 7

By definition, complex diseases are caused by variation in many genes, and they may or may not be influenced by environment.

Question 8

Give some examples of multifactorial diseases

Answer 8

Examples of these conditions include cardiovascular disease, cancer, diabetes, and a number of birth defects and psychiatric disorders.

Question 9

What is a mutation?

Answer 9

Mutation is a jumping stable change of the genetic apparatus (not connected with cell division or usual chromosomal recombination) and a material basis of genetically determined diseases.

Question 10

Give ten types of mutations and describe them

Answer 10

Substitution - change in nucleotide
-Missense variant - change in amino acid
-Nonsense variant - stop signal introduced
Insertion - inserting one or more nucleotides
Deletion - deleting one or more nucleotides
Deletion-insertion
Duplication - a stretch of DNA is duplicated and placed adjacent to the original part of the sequence
Inversion - more than one nucleotide is replaced with the same sequence in reverse order
Frameshift - shift by 3 nucleotides due to deletion, insertion or duplication
Repeat expansion

Question 11

Give three causes of mutation in order of potency

Answer 11

Physical (like radiation), chemical and biological

Question 12

Give some examples of biological mutagens

Answer 12

Biological mutagens are certain viruses such as measles, chickenpox, mumps, infectious nucleosis. Rubella in pregnant women is associated with infantile malformations.

Question 13

Give methods by which the body protects against mutations

Answer 13

Antioxidant biochemical system prevents mutation , neutralises active forms of oxygen which belong to endogenous mutagens.
Mutations can be recognised and repaired by means of various endogenous enzymes such as polymerase and ligase.
B lymphocytes recognise mutated cells and mark them with immune globulins to be destroyed by T cells and phagocytes.

Question 14

How does radiation result in mutations?

Answer 14

Ionising radiation directly affects the DNA molecules in cells due to its ability to penetrate deep into the human body. It breaks chemical bonds within the DNA double helix and any errors in repair that follow this are deemed mutations.

Question 15

How do chemicals result in mutations?

Answer 15

The most potent chemical mutagens are purines and pyrimidines which may cause the wrong nucleotides to be placed in the wrong places during DNA replication and repair.

Question 16

How do biological agents cause mutations?

Answer 16

Biological mutagens are certain viruses such as measles, chickenpox, mumps, infectious nucleosis. Rubella in pregnant women is associated with infantile malformations.

Question 17

What are chromosomal alterations?

Answer 17

Mutations that change chromosome structure

Question 18

How do chromosomal alterations occur?

Answer 18

They occur when a section of a chromosome breaks off and rejoins incorrectly or does not rejoin at all.

Question 19

How do quantitative changes of chromosomes occur?

Answer 19

The quantitative changes of chromosomes result from nondisjunction of homologous chromosomes during gametogenesis or at the early stage of zygote splitting.

Question 20

Give examples of autosomal dominant diseases

Answer 20

Huntington’s disease, achondroplasia, sickle-cell anaemia, sperocytosis/haemolytic anamia and thalassaemia.

Question 21

Are the majority of sex linked disorders X-linked or Y-linked?

Answer 21

X-linked

Question 22

Are the majority of sex linked disorders dominant or recessive?

Answer 22

Recessive. A heterozygous female with an X-linked mutant allele is normal because of the normal paired allele.

Question 23

Give some examples of sex linked conditions

Answer 23

Examples include diabetes insipidus, G6PD defieciency (haemolytic anaemia), haemoplilia A and B (haemorrhge syndrome), colour blindness, juvenile glaucoma.

Question 24

Give some examples of autosomal recessive conditions

Answer 24

Enzymopathy, haemoglobinopathy, erythrocytopathy, coagulopathy and metabolic diseases are inherited in such a way. Besides, here belong androgenital syndrome (endocrinopathy), agammaglobulinemia (immunodeficiency), glycogen storage disease, galactosemia, phyenylketonuria and muscular dystrophy.

Question 25

How likely is it that a mutated germ cell containing a chromosomal abnormality to go on to produce a live child?

Answer 25

It is highly unlikely that a mutated germ cell cell could go on to be impregnated, form a viable embryo and result in a live newborn.

Question 26

In what percentage of live births containing a chromosomal abnormality is fertility preserved? Can the abnormality be inherited by offspring?

Answer 26

If the reproductive function is preserved (3-5% of cases) posterity inherits the chromosomal abnormality.

Question 27

Do qualitative or quantitative chromosomal abnormalities have more severe consequences?

Answer 27

Qualitative

Question 28

What are the common features of children born with chromosomal abnormalities?

Answer 28

The patients require constant medical assistance because of serious physical handicaps and mental retardation. Most children die young. Predisposition to the development of immunodeficiency, allergy, neoplasia and leukaemia is detected.

Question 29

How did Hippocrates define constitutional types?

Answer 29

CHOLERIC - people with yellow bile. Hot blooded, irritable, restless, passionate, bold and eager
MELANCHOLIC - people with predominance of black bile. Sad, reserved, depressed and devoid of all hope in life
SANGUINIC - blood content is high in such people. Cheerful, happy and optimistic in life.
PHLEGMATIC - predominance of phlegm. Calm, quiet, relaxed and reliable behaviour.

Question 30

How did D. R. Sigaud distinguish constitutional types?

Answer 30

(1) respiratory, characterized by marked development of the chest;
(2) digestive, characterized by a large abdomen, a well-developed lower third of the face, and a short neck;
(3) muscular, characterized by well-developed muscles, a broad chest, a well-proportioned physique, and a square face; and
(4) cerebral, characterized by a large skull, a pronounced forehead, a slim figure, and poorly developed muscles.

Question 31

How did the German scientist E. Kretschmer distinguish constitutional types?

Answer 31

asthenic, pyknic, and athletic types.

Question 32

What constitutional types did Pavlov distinguish in humans?

Answer 32

(1) the artistic, in which the first signaling system is relatively dominant and thought is predominantly graphic and concrete;
(2) the intellectual, in which the second signaling system is relatively dominant and thought is predominantly abstract; and
(3) the intermediate, which occupies a position between the other two.
The relationship between the first and second signaling systems and the dominance of either may vary with upbringing, life conditions, and disease.

Question 33

What is aging at a biological level?

Answer 33

At the biological level, ageing results from the impact of the accumulation of a wide variety of molecular and cellular damage over time. This leads to a gradual decrease in physical and mental capacity, a growing risk of disease and ultimately death.

Question 34

What else might affect aging aside from biological factors?

Answer 34

Beyond biological changes, ageing is often associated with other life transitions such as retirement, relocation to more appropriate housing and the death of friends and partners.

Question 35

What illnesses become more common as aging progresses?

Answer 35

Common conditions in older age include hearing loss, cataracts and refractive errors, back and neck pain and osteoarthritis, chronic obstructive pulmonary disease, diabetes, depression and dementia. As people age, they are more likely to experience several conditions at the same time.
Older age is also characterized by the emergence of several complex health states commonly called geriatric syndromes. They are often the consequence of multiple underlying factors and include frailty, urinary incontinence, falls, delirium and pressure ulcers.

Question 36

What are the three major theories of aging?

Answer 36

There are three major psychosocial theories of aging–activity theory, disengagement theory, and continuity theory.

Question 37

What is the activity theory of aging?

Answer 37

The activity theory of aging proposes that older adults are happiest when they stay active and maintain social interactions. These activities, especially when meaningful, help the elderly to replace lost life roles after retirement and, therefore, resist the social pressures that limit an older person’s world.

Question 38

What is the disengagement theory of aging?

Answer 38

The disengagement theory of ageing states that “aging is an inevitable, mutual withdrawal or disengagement, resulting in decreased interaction between the aging person and others in the social system he belongs to”.[1] The theory claims that it is natural and acceptable for older adults to withdraw from society.[2] There are multiple variations on disengagement theory, such as moral disengagement.

Question 39

What is the continuity theory of aging?

Answer 39

The continuity theory of normal aging states that older adults will usually maintain the same activities, behaviors, relationships as they did in their earlier years of life.[1] According to this theory, older adults try to maintain this continuity of lifestyle by adapting strategies that are connected to their past experiences.

Question 40

What is the connection between aging and disease?

Answer 40

Ageing is associated with a progressive degeneration of the tissues, which has a negative impact on the structure and function of vital organs and is among the most important known risk factors for most chronic diseases.

Question 41

What is progeria?

Answer 41

Progeria is a specific type of progeroid syndrome, also known as Hutchinson-Gilford syndrome. Progeroid syndromes are a group of diseases that cause victims to age faster than usual, leading to them appearing older than they are. Patients born with progeria typically live to an age of mid-teens to early twenties.[6][7]
Severe cardiovascular complications usually develop by puberty, resulting in death.

Mental development is not adversely affected; in fact, intelligence tends to be average to above average.[43] With respect to the features of aging that progeria appears to manifest, the development of symptoms is comparable to aging at a rate eight to ten times faster than normal. With respect to features of aging that progeria does not exhibit, patients show no neurodegeneration or cancer predisposition. They also do not develop conditions that are commonly associated with ageing, such as cataracts (caused by UV exposure) and osteoarthritis.[31]
Although there may not be any successful treatments for progeria itself, there are treatments for the problems it causes, such as arthritic, respiratory, and cardiovascular problems. Sufferers of progeria have normal reproductive development, and there are known cases of women with progeria who delivered healthy offspring

Question 42

What syndromes are associated with changing of the number of somatic chromosomes. Give them a brief description.

Answer 42

ACHONDROPLASIA - short stature, short limbs, large head, most cases sporadic due to a new mutation
ACHONDROPLASIA - milder version of the above
EHLERS DANLOS SYNDROME - hyperextensible joints and skin, easy bruisability
MARFAN’S SYNDROME - tall, thin habitus, abnormal sternum, dislocated lenses, arachnodactyly, heart defect
MYOTONIC DYSTROPHY - hypotonia, weakness, mental retardation
OSTEOGENESIS IMPERFECTA - blue sclera, fracture easily, short stature
TUBEROUS SCLEROSIS - infantile spasms, mental retardation, depigmented areas of skin, adenoma sebaceum over nose and cheeks
WAARDENBURNG SYNDROME - white forelock, dystopia canthorum, sensorineural weakness.