1 GENE MUTATION

Question 1

is a permanent alteration in the DNA
sequence of a gene.

Answer 1

Gene mutation

Question 2

This change can affect the protein that the gene codes for,
potentially leading to a variety of consequences for the
organism.

Answer 2

Gene mutation

Question 3

CLASSIFICATIONS OF GENE MUTATIONS

Answer 3

HEREDITARY MUTATIONS
ACQUIRED (OR SOMATIC) MUTATIONS
DE NOVO (NEW) MUTATIONS
MOSAICISM

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Are inherited from a parent and are present throughout a
person’s life in virtually every cell in the body

Answer 4

Hereditary Mutations

Question 5

HEREDITARY MUTATIONS is also called as

Answer 5

Germline Mutations

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Fertilized egg cell receives DNA from both parents

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Hereditary Mutations

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Occur at some time during a person’s life

Answer 7

ACQUIRED (OR SOMATIC) MUTATIONS

Question 8

Present only in certain cells, not in every cell in the body.

Answer 8

ACQUIRED (OR SOMATIC) MUTATIONS

Question 9

ACQUIRED (OR SOMATIC) MUTATIONS is caused by

Answer 9

environmental factors such as UV radiation.

Question 10

Acquired mutations in somatic cells

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ACQUIRED (OR SOMATIC) MUTATIONS

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Cannot be passed to the next generation

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ACQUIRED (OR SOMATIC) MUTATIONS

Question 12

Hereditary or somatic

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DE NOVO (NEW) MUTATIONS

Question 13

Genetic disorders in which an affected child has a
mutation in every cell in the body but the parents do not

Answer 13

DE NOVO (NEW) MUTATIONS

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There is no family history of the disorder

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DE NOVO (NEW) MUTATIONS

Question 15

Somatic mutations that happen in a single cell early in
embryonic development

Answer 15

MOSAICISM

Question 16

Not present in a parent’s egg or sperm cells, or in the
fertilized egg, but happen a bit later when the embryo
includes several cells.

Answer 16

MOSAICISM

Question 17

May or may not cause health problems

Answer 17

MOSAICISM

Question 18

CAUSES OF GENE MUTATION

Answer 18

ERRORS IN DNA REPLICATION
ERRORS IN DNA RECOMBINATION
CHEMICAL DAMAGE TO DNA
RADIATION

Question 19

DNA polymerase will incorporate a non-complementary
base into the daughter strand

Answer 19

ERRORS IN DNA REPLICATION

Question 20

The mis-incorporated base would lead to a mutation

Answer 20

ERRORS IN DNA REPLICATION

Question 21

Very rare as the exonuclease functions as a proofreading

Answer 21

ERRORS IN DNA REPLICATION

Question 22

DNA often rearranges itself by a process called
recombination which proceeds via a variety of
mechanisms

Answer 22

ERRORS IN DNA RECOMBINATION

Question 23

DNA is lost during replication leading to a mutation

Answer 23

ERRORS IN DNA RECOMBINATION

Question 24

Chemical mutagens, some exogenous, some man-made,
some environmental, are capable of damaging DNA.

Answer 24

CHEMICAL DAMAGE TO DNA

Question 25

Chemical mutagens, some exogenous, some man-made, some environmental, are capable of damaging DNA.

Answer 25

CHEMICAL DAMAGE TO DNA

Question 26

gamma rays, uv

Answer 26

RADIATION

Question 27

Many chemotherapeutic drugs are intercalating agent drugs that function by damaging DNA.

Answer 27

chemical damage to dna

Question 28

TYPES OF GENE MUTATION

Answer 28

POINT MUTATION CHROMOSOMAL MUTATION COPY NUMBER VARIATION SOMATIC MUTATION

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TYPES OF POINT MUTATIONS

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Single Mutation Neutral Mutation Missense Mutation Nonsense Mutation

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Single base modification

Answer 30

POINT MUTATION

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Type of mutation that causes a single nucleotide base substitution, insertion, or deletion of the genetic material, DNA or RNA.

Answer 31

POINT MUTATION

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Frameshift mutation indicates the addition or deletion of a base pair.

Answer 32

POINT MUTATION

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(TYPE OF POINT MUTATION) Single-base alteration with no significant change in the amino acid sequence

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Single Mutation

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(TYPE OF POINT MUTATION) Single-base change producing a different amino acid with a similar function.

Answer 34

Neutral Mutation

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(TYPE OF POINT MUTATION) Single-base change resulting in a different amino acid with altered function.

Answer 35

Missense Mutation

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(TYPE OF POINT MUTATION) Single-base change leading to a premature stop codon.

Answer 36

Nonsense Mutation

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A mutation involving a long segment of DNA

Answer 37

CHROMOSOMAL MUTATION

Question 38

These mutations can involve deletions, insertions, or inversions of sections of DNA

Answer 38

CHROMOSOMAL MUTATION

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CHROMOSOMAL MUTATION is also Also referred to as a

Answer 39

Chromosomal Arrangement

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Genome are repeated and the number of repeats in the genome varies between individuals in the human population

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COPY NUMBER VARIATION

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Genetic alteration acquired by a cell that can be passed to the progeny of the mutated cell in the course of cell division.

Answer 41

SOMATIC MUTATION

Question 42

_________ differ from germline mutations

Answer 42

Somatic mutations

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Autosomal recessive genetic condition causing severe lung damage and nutritional deficiencies

Answer 43

CYSTIC FIBROSIS

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CYSTIC FIBROSIS is mainly caused by

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mutations in both alleles of the CFTR gene, leading to loss of function.

Question 45

regulates chloride transport, resulting in thick and sticky mucus, affecting respiratory function.

Answer 45

CFTR

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IMPACT OF CFTR MUTATION

Answer 46

Dysregulation of chloride, sodium, and water transport leads to increased salt concentration in sweat. Over 2,000 CFTR mutations are linked to cystic fibrosis, with the most common being a 3-bp deletion at position 508.

Question 47

Autosomal dominant genetic condition leading to significantly elevated LDL-cholesterol levels and increased risk of premature cardiovascular disease.

Answer 47

FAMILIAL HYPERCHOLESTEROLEMIA (FH)

Question 48

Can manifest as homozygous or heterozygous FH, with homozygous FH causing a severe LDL-C level phenotype

Answer 48

FAMILIAL HYPERCHOLESTEROLEMIA (FH)

Question 49

CAUSES OF FH

Answer 49

Mainly attributed to genetic mutations in the LDLR gene, which encodes the LDL receptor. Other causes include mutation in the APOB gene (apolipoprotein B-100 gene), gain of function (GOF) mutation in the PCSK9 gene, and loss of function (LOF) mutation in the LDLRAP1 gene.

Question 50

X-linked recessive genetic disorder resulting from a deficiency in coagulation factor VIII (FVIII) encoded by the F8 gene.

Answer 50

HEMOPHILIA A

Question 51

Mutations associated with ______ include deletion, duplication, insertion, insertion/deletion, inversion, and substitution, with about 40% of cases caused by inversions.

Answer 51

hemophilia A

Question 52

CLASSIFICATION AND SYMPTOMS OF HEMOPHELIA A

Answer 52

● Hemophilia A can be categorized as severe, moderate, or mild based on FVIII coagulant activity levels in the plasma ● Patients experience prolonged bleeding, delayed blood clotting after injury, renewed or spontaneous bleeding, which can be life-threatening. ● Joint bleeding can lead to arthropathy, impacting mobility, and quality of life.

Question 53

A heterogenous group of diseases characterized by anemia and the presence of ring sideroblasts in the bone marrow.

Answer 53

CONGENITAL SIDEROBLASTIC ANEMIA (CSA)

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While primarily congenital, cases of acquired forms have also been reported.

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CONGENITAL SIDEROBLASTIC ANEMIA (CSA)

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GENETIC BASES AND MUTATIONS

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● The congenital form is often X-linked and linked to mutations in genes related to heme biosynthesis, iron-sulfur cluster biosynthesis, and mitochondrial protein synthesis. ● Mutations in the erythroid-specific delta-aminolevulinic synthase (ALAS2) gene, crucial for heme biosynthesis, are a common cause of CSA. ● Mutations leading to decreased ALAS2 activity contribute to CSA, while increased activity may result in X-linked erythropoietic protoporphyria.

Question 57

Hematologic disorder characterized by increased iron absorption and excessive iron storage in various organs.

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HEREDITARY HEMOCHROMATOSIS

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HEREDITARY HEMOCHROMATOSIS

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Iron deposition commonly seen in the liver, heart, joints, pituitary gland, and pancreas

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● Unaffected individuals absorb 1 to 2 mg of iron per day, while those with hemochromatosis can absorb up to 30 g daily. ● Excess iron absorption leads to iron overload and storage issues in multiple issues.

Answer 59

IRON ABSORPTION AND STORAGE

Question 60

Unaffected individuals absorb___ of iron per day, while those with hemochromatosis can absorb up to ___ daily.

Answer 60

1 to 2 mg; 30 g

Question 61

GENETIC BASIS AND MUTATIONS

Answer 61

Mutations in the HFE gene, encoding the β₂- microglobulin-associated protein, are commonly associated with hereditary hemochromatosis. ● Varying phenotypic expression has linked hemochromatosis to other genes related to hereditary anemia.

Question 62

TYPES OF HEREDITARY HEMOCHROMATOSIS

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Type 1 Type 2A, 2B, 3 & 4

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(TYPE OF HEREDITARY HEMOCHROMATOSIS) Classic form associated with variations in the HFE gene.

Answer 63

Type 1

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(TYPE OF HEREDITARY HEMOCHROMATOSIS) Related to genes such as TfR2, HJV, HAMP , and ferroportin 1, respectively

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Type 2A, 2B, 3, and 4

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MISSENSE MUTATIONS IN HFE GENE

Answer 65

o C2B2Y mutation: Cysteine-to-tyrosine substitution disrupting disulfide bridges o H63D mutation: Aspartic acid to-histidine conversion. o S65C mutation: Serine-to-cysteine conversion leading to milder forms of hemochromatosis.

Question 66

Anemia characterized by sickle-shaped red blood cells due to a mutation in the protein globin

Answer 66

SICKLE CELL ANEMIA

Question 67

Disorder characterized by an extra copy of chromosome 21 or partial duplication of its long-arm region (q22.1 to 22.3).

Answer 67

DOWN SYNDROME

Question 68

Female chromosomal abnormality characterized by partial or complete absence of an X chromosome (monosomy X) in some or all cells.

Answer 68

TURNER SYNDROME

Question 69

DETECTION OF GENE MUTATIONS Biochemical Methods

Answer 69

○ Enzyme Immunoassays ○ Immunohistochemistry ○ High-Performance Liquid Chromatography (HPLC) ○ Gas Chromatography ○ Mass Spectrometry