Introduction to Pathology Flashcards

Question

Definition [1] and causes of non-genetic congenital diseases [2]

Answer 1

When the parents do not have an genetic problems but the child is born with the abnormality -- something goes wrong when the fetus is in the womb Causes: 1. TORCH complex 2. Iatrogenic

Answer 2

1. TORCH complex (refers to a complex of similar abnormalities produced by fetal / neonatal infection) e.g. Toxoplasma - exposure to cat faeces, undercooked contaminated meat or mother-to-child transmission during pregnancy rubella and herpes simplex virus Intrauterine infections by the rubella virus can cause cardiac, cerebral, ophthalmic and auditory defects in the fetus.

Answer 3

1. Fetal alcohol syndrome - Babies exposed to alcohol in the womb are more prone to problems e.g. poor growth, small sunken eyes, depressed nose, learning disorders and behavioural problems 2. Drugs: thalidomide It's use in pregnancy causes birth defects

Answer 4

Weeks 5-8 of gestation - development of major organ systems During this time, the embryo is extremely susceptible to the effects of teratogens (substance that may lead to birth defects)

Answer 5

Deletion, Inversion and translocation Any deviation from the norm has the potential to cause disease

Answer 6

A mutation in which a part of a chromosome / sequence of DNA is lost during DNA replication. Deletions that do not occur in multiples of three bases cause a frameshift by changing the 3-nucleotide protein reading frame of the genetic sequence. example - cri du chat syndrome (5p-)

Answer 7

A chromosome rearrangement in which a segment of a chromosome is reversed end to end. Occurs when a single chromosome undergoes breakage and rearrangement within itself most common inversion = chromosome 9 - usually no harmful effects

Answer 8

Chromosome abnormality caused by rearrangements of parts between nonhomologous chromosomes - balance (even exchange of material with no genetic information extra or missing, and ideally full functionality) - or unbalanced (unequal exchange of material resulting in extra or missing genes) Example - 5q syndrome

Answer 9

Inherited defective genes Mitochondrial inheritance Acquired defective gene

Answer 10

Monogenic (caused my a mutation in a single gene) e.g. cystic fibrosis & sickle cell anemia or Polygenic AKA polygenic inheritance – associated with effects of multiple genes in combination with environmental factors. Examples include: - Diabetes, hypertension, atherosclerosis, asthma, autoimmune diseases and cleft lip and palate

Answer 11

Mediated by mitochondrial genes, which are inherited by maternal transmission. 100% chance that each child in the family will inherit a mitochondrial gene

Answer 12

After birth e.g. neoplasms (tumors)

Answer 13

Etiology - caused by mutation in a single nucleotide - substitution (A to T) in the codon for amino acid 6 The change converts a glutamic acid codon (GAG) to a valine codon (GTG) GAG - normal Hb A GTG - Hbs (form of haemoglobin in a person with sickle cell anemia) It is an autosomal recessive disorder = in order for full disease symptoms to manifest in an individual they must carry two copies of the HbS gene. Individuals who are heterozygous have a sickle cell trait. Clinically normal, but their RBCs can sickle under very low oxygen pressure.

Answer 14

Allele – alternative form of a gene that is located at a specific position on a specific chromosome Homozygous – both genes are the same for that organism is homozygous for the trait Heterozygous – both genes are different for that organism is heterozygous for that trait

Answer 15

Autosomal dominant Autosomal recessive X-linked recessive

Answer 16

Only one abnormal copy of the paired gene is required to manifest the disease e.g. FH, marfans syndrome

Answer 17

Both copies of the paired gene are required to be abnormal to manifest the disease if you carry 1 copy of the abnormal gene = carrier e.g. cystic fibrosis, Ataxia Telangiectasia (AT)

Answer 18

Usually occur in males as they have only one X chromosome e.g. haemophilia Females can get an X-linked recessive disorder, but this is very rare. - the other X compensates but men only have one X chromosome An abnormal gene on the X chromosome from each parent would be required

Answer 19

Turner syndrome (45X) Klinefelter syndrome (47XXY)

Answer 20

Down syndrome Caused by the presence of an extra chromosome 21 - trisomy 21 Incidence of down syndrome increases with maternal age

Answer 21

- shortening of all parts of the body - a wide and flat face with a small nose - associations with congenital heart disease - increased risk for specific leukemia and immunological deficiencies - mental retardation

Answer 22

Gram-positive and gram-negative bacteria Gram positive: Staphylococcus Streptococcus Clostridium Listeria Cornybacterium Nocardia Mycoplasma Gram negative: Salmonella Shigella E-coli Klebsella Pseudomonas Neisseria Hemophilus

Answer 23

A) Direct cytopathic effect B) Induction of immune lysis C) Neoplastic transformation