Patho Genetics and Epigenetics - Lecture 2

DNA is _________ into RNA

transcribed

RNA is ________ into protein

translated

What are the 2 major roles of DNA?

replication and protein construction

What travels along the single strand, adding complementary bases and proofreading the strands to ensure appropriate bases are added?

DNA polymerase

What type of DNA replication makes two identical cells (46 chromosomes)?

mitosis 

What type of DNA replication makes 4 unique cells (23 chromosomes)?

meiosis

What base is only found in RNA?

uracil

What binds to the promoter region of the DNA and copies DNA making mRNA until STOP codon?

RNA polymerase

What brings amino acids to the ribosome to construct the polypeptide chain through complementary strand matching?

Transfer RNA

What are made of 3 nucleotides (codons)?

amino acids

What are one or more long, folded chains of amino acids, whose sequences are determined by the DNA sequence of the protein-encoding gene?

protein

What is the dysfunction of protein cause?

genetic disease

What are the basic units of inheritance, passed from parents to offspring, that code for specific proteins or segments of proteins?

genes

Everyone has the gene for the disease, but we might not have what codes for the disease?

variants

What refers to a trait or variants encoded in DNA and passed from offspring during reproduction?

inheritance

What is a chart that diagrams the inheritance of a trait or health condition through generations of a family?

pedigree

What is one of two or more versions of a DNA sequence (a single base or a segment of bases) at a given genomic location?

allele

If a patient has 2 alleles that are the same, the individual is what?

homozygous

If a patient has 2 different alleles that are different, the individual is what?

heterozygous

What is the person’s genetic code called?

genotype

What is the person’s outward appearance combination of genetics and exposures?

phenotype

What is a change in the DNA sequence of an organism?

mutation

What causes a mutation?

errors in DNA replication during cell division, exposure to mutagens, viral infection

What is a mutation that occurs in eggs and sperm that can be passed to offspring?

germline mutations

What is a mutation that occurs in body cells that is not passed on to offspring?

somatic mutation 

What type of single-point mutation does not change the coded amino acid?

silent

What type of single-point mutation that does changes the amino acid?

missense

What type of single-point mutation changes to a stop codon?

nonsense

What type of single-point mutation adds or deletes a nucleotide?

frameshift

What disease is caused by a missense mutation?

sickle cell disease

What disease is caused by a nonsense mutation?

cystic fibrosis

What disease is caused by a frameshift?

hypertrophic cardiomyopathy

What disease is caused by a frameshift mutation?

HIV resistance

What is a disorder that means that the gene is located on one of the numbered or non-sex chromosomes?

autosomal

What does it mean when a single copy of a mutated gene from one parent is enough to cause the disorder?

dominant

In an autosomal dominant disorder, what do you need to inherit the disorder?

one copy of the gene - no carriers

What does it mean to have 2 copies of the mutated gene, one from each parent are required to cause the disorder?

recessive 

In an autosomal recessive disorder, what do you need to inherit to have the disorder?

two copies of the gene - has carriers 

What are disorders that are inherited from the sex chromosomes?

sex-linked disorder

What chromosome is a sex-linked disease normally found on?

X

What type of inheritance is when multiple genes together inform the phenotype?

polygenic

What type of inheritance is when environmental factors influence the expression of the trait?

multifactorial

What can you not see with a pedigree?

polygenic and multifactorial inheritance

What is the kind of chromosome abnormality where the number of chromosomes in a cell is due to loss or duplication?

aneuploidy

What usually causes aneuploidy?

errors in meiosis

What disease is caused by aneuploidy?

down syndrome 

What type of chromosomal abnormalities happen with the crossover of genes?

recombination

What type of chromosomal abnormalities happen when a gene is deleted?

deletions

What type of chromosomal abnormalities happen when genes duplicate?

duplications

What type of chromosomal abnormalities happen when genetic info is flipped upside down?

inversions 

What type of chromosomal abnormalities happen when a portion of a chromosome moves to a different chromosome?

translocations

What type of chromosomal abnormalities happen in early development when some sort of abnormality happens and all cells that come from that line have it?

mosaics

What is more damaging than duplication of a gene?

deletion

What disease is a hereditary neurodegenerative disorder characterized by motor dysfunction, cognitive decline, and psychiatric symptoms inherited?

Huntington Disease

What type of chromosomal disorder is Huntington's disease?

autosomal dominant

What causes Huntington's disease?

by CAG repeat in the HTT gene, causing an abnormal shape that accumulates in the brain, causing neuron cell death 

What is the biggest manifestation of Huntington's disease?

chorea

How do you diagnose Huntington's disease?

family hx and genetic testing

What is a disease is a hereditary blood disorder characterized by RBC that assume an abnormal, rigid, sickle shape, leading to reduced oxygen delivery to issues, pain, and other complications?

sickle cell disease

What type of chromosomal disorder is sickle-cell disease?

autosomal recessive

What causes sickle cell disease?

homozygous point mutation in the HBB gene, which encodes the beta globin chain of Hb, HbS sticks together under low oxygen conditions, leading to the formation of RBCs into a sickle shape, resulting in blockages, RBC rupture, and decreased oxygen to tissues

What is an acute complication of sickle cell disease?

vaso-occlusive pneumonia - bone infarction, MI, stroke, kidney infarct

How do you diagnose sickle cell disease?

hx, physical, newborn genetic testing

What disease is a hereditary bleeding disorder characterized by the deficiency or dysfunction of specific clotting factors, leading to prolonged bleeding and easy bruising?

hemophilia

What type of chromosomal disorder is hemophilia?

sex-linked recessive 

What causes hemophilia?

mutations on F8 or F9 gene such as insertions, deletions or inversions 

How is hemophilia manifested?

Age at first bleeding and sites of bleeding

What is hemophilia first seen at in infants?

CNS

How do you diagnose hemophilia?

hx, physical, screening

What disease is a genetic disorder characterized by distinct physical features, intellectual disability, and often, specific medical and developmental challenges?

down syndrome

What type of chromosomal disorder causes Down syndrome?

aneuploidy

What causes down syndrome?

presence of all or part of the 3rd copy of chromosome 21(nondisjunction: failure of chromosome 21 to separate properly during cell division and translocation: segment of chromosome 21 get detached and attaches to another chromosome

How does Down syndrome manifest?

mental delay, facial features, cardiac defects, GI malformations, visual and hearing impairments, thyroid dysfunction, leukemia

How do you diagnose Down syndrome?

prenatal screening - ultrasound or quad screen, prenatal diagnostic - chronic villi sampling or amniocentesis, diagnosis after birth - physical exam