Genetic mutations Genetic Mutations Carcinogenesis are errors in DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Chromosomal mutations occur when an abnormal number of chromosomes Chromosomes In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. DNA Types and Structure is inherited. Point mutations occur when a nucleotide is swapped for another nucleotide and can be missense, nonsense, or silent mutations. Frameshift mutations occur when a nucleotide is added or deleted, and expansion mutations occur when a given trinucleotide sequence is repeated along the chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics. Genetic mutations Genetic Mutations Carcinogenesis are the basis for most inherited diseases. Common disorders caused by DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure mutations include sickle cell disease Sickle cell disease Sickle cell disease (SCD) is a group of genetic disorders in which an abnormal Hb molecule (HbS) transforms RBCs into sickle-shaped cells, resulting in chronic anemia, vasoocclusive episodes, pain, and organ damage. Sickle Cell Disease, Huntington disease Huntington disease Huntington disease (HD) is a progressive neurodegenerative disorder with an autosomal dominant mode of inheritance and poor prognosis. It is caused by cytosine-adenine-guanine (CAG) trinucleotide repeats in the huntingtin gene (HTT). The most common clinical presentation in adulthood is a movement disorder known as chorea: abrupt, involuntary movements of the face, trunk, and limbs. Huntington Disease, and Tay-Sachs disease Tay-Sachs disease Tay-Sachs disease is an autosomal recessive lysosomal storage disorder caused by genetic mutations in the hexosaminidase A (HEXA) gene, leading to progressive neurodegeneration. Classic symptoms in infants include rapid degeneration of cognitive and neuromuscular abilities, progressive blindness, and a macular cherry-red spot on physical examination. Tay-Sachs Disease.
Last updated: 29 Nov, 2021
Chromosomal numerical abnormalities occur when there is a gain or loss of an entire chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics.
Monosomy is a loss of 1 chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics (pair becomes 1 chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics):
Trisomy is a gain of 1 chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics (pair becomes 3 chromosomes Chromosomes In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. DNA Types and Structure):
Webbed neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess, seen in Turner syndrome Turner syndrome Turner syndrome is a genetic condition affecting women, in which 1 X chromosome is partly or completely missing. The classic result is the karyotype 45,XO with a female phenotype. Turner syndrome is associated with decreased sex hormone levels and is the most common cause of primary amenorrhea. Turner Syndrome
Image: “Preoperative photo” by Imen Mehri Turki. License: CC BY 4.0Facial features of a baby with Down syndrome Down syndrome Down syndrome, or trisomy 21, is the most common chromosomal aberration and the most frequent genetic cause of developmental delay. Both boys and girls are affected and have characteristic craniofacial and musculoskeletal features, as well as multiple medical anomalies involving the cardiac, gastrointestinal, ocular, and auditory systems. Down syndrome (Trisomy 21)
Image: “A drawing of the facial features of Down syndrome Down syndrome Down syndrome, or trisomy 21, is the most common chromosomal aberration and the most frequent genetic cause of developmental delay. Both boys and girls are affected and have characteristic craniofacial and musculoskeletal features, as well as multiple medical anomalies involving the cardiac, gastrointestinal, ocular, and auditory systems. Down syndrome (Trisomy 21)” by Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities. License: Public DomainA point mutation is a mutation that affects only 1 nucleotide in a DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure sequence. The nucleotide change can lead to the following outcomes:
Silent mutation:
A silent mutation is a single nucleotide substitution that results in the
translation
Translation
Translation is the process of synthesizing a protein from a messenger RNA (mRNA) transcript. This process is divided into three primary stages: initiation, elongation, and termination. Translation is catalyzed by structures known as ribosomes, which are large complexes of proteins and ribosomal RNA (rRNA).
Stages and Regulation of Translation of the same
amino acid
Amino acid
Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group).
Basics of Amino Acids. Thus, protein function is not affected.
Met
MET
Preoperative Care: methionine
Pro:
proline
Proline
A non-essential amino acid that is synthesized from glutamic acid. It is an essential component of collagen and is important for proper functioning of joints and tendons.
Synthesis of Nonessential Amino Acids
Thr: threonine
Arg:
arginine
Arginine
An essential amino acid that is physiologically active in the l-form.
Urea Cycle
Missense mutation:
Missense mutations result when a change of a single base pair causes the substitution of a different
amino acid
Amino acid
Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group).
Basics of Amino Acids in the resulting protein. Amino acid substitution may have no effect or may render the protein nonfunctional.
Met
MET
Preoperative Care: methionine
Pro:
proline
Proline
A non-essential amino acid that is synthesized from glutamic acid. It is an essential component of collagen and is important for proper functioning of joints and tendons.
Synthesis of Nonessential Amino Acids
Thr: threonine
His: histidine
Nonsense mutation:
A sense
codon
Codon
A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal. Most codons are universal, but some organisms do not produce the transfer RNAs complementary to all codons. These codons are referred to as unassigned codons.
Basic Terms of Genetics that corresponds to 1 of the 20 amino
acids
Acids
Chemical compounds which yield hydrogen ions or protons when dissolved in water, whose hydrogen can be replaced by metals or basic radicals, or which react with bases to form salts and water (neutralization). An extension of the term includes substances dissolved in media other than water.
Acid-Base Balance specified by the genetic code is changed to a stop
codon
Codon
A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal. Most codons are universal, but some organisms do not produce the transfer RNAs complementary to all codons. These codons are referred to as unassigned codons.
Basic Terms of Genetics.
Met
MET
Preoperative Care: methionine
Pro:
proline
Proline
A non-essential amino acid that is synthesized from glutamic acid. It is an essential component of collagen and is important for proper functioning of joints and tendons.
Synthesis of Nonessential Amino Acids
Frameshift mutation:
Frameshift mutations can be due to the addition or insertion of
nucleotides
Nucleotides
The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group.
Nucleic Acids that changes the length of the
gene
Gene
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
Basic Terms of Genetics, thus affecting protein
synthesis
Synthesis
Polymerase Chain Reaction (PCR).
His: histidine
Trinucleotide repeat expansion (repeat expansion mutation) in relation to point mutations and insertion mutations
Met
MET
Preoperative Care: methionine
Pro:
proline
Proline
A non-essential amino acid that is synthesized from glutamic acid. It is an essential component of collagen and is important for proper functioning of joints and tendons.
Synthesis of Nonessential Amino Acids
Thr: threonine
His: histidine
Ser:
serine
Serine
A non-essential amino acid occurring in natural form as the l-isomer. It is synthesized from glycine or threonine. It is involved in the biosynthesis of purines; pyrimidines; and other amino acids.
Synthesis of Nonessential Amino Acids
Gln:
glutamine
Glutamine
A non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from glutamic acid and ammonia. It is the principal carrier of nitrogen in the body and is an important energy source for many cells.
Synthesis of Nonessential Amino Acids
Leu: leucine