Genetics Flashcards
(42 cards)
1
Q
Congenital
A
Present at birth, inherited, genetic or developmental defects due to damage in utero
2
Q
Genetic
A
Consequences of gene changes to the 23 chromosomes in each cell
3
Q
Chromosomal
A
Abnormal or dislocation of chromosomes
4
Q
Developmental
A
Damage to body structures during development or shortly after birth
5
Q
Multifactorial
A
Combo of genetic predisposition and exposure
6
Q
Chromosome
A
DNA storage unit
- threadlike strands of DNA wrapped around protein in each cell nucleus which transmits genetic info
- human DNA organized into 2 sets of 23 (22 = autosomal, 23rd = sex)
- XX female, XY male
7
Q
Genes
A
- instruction manual
- code for cells to make protein molecules
- two copies of each gene
- 25000 genes
8
Q
Alleles
A
DNA sequence of a particular gene that occupies a given location on a chromosome - rungs
- “functional unit”
- dominant and recessive
- in an organism that has two copies of each chromosome, two alleges make up the individual’s genotype
9
Q
Genotype
A
- an individual’s collection of genes, genetic make up or allele combination
- refers to the two alleles inherited from a particular gene (one from each parent)
10
Q
Phenotype
A
- expression of the genotype contribute to the individual’s observable traits
11
Q
Epigenetics
A
The study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself
12
Q
Dominant traits
A
Occurs when one gene is sufficient to express a trait
- masks the presence of a recessive gene
- can be inherited from a single parent
13
Q
Recessive trait
A
Expressed only when two copies of the gene are present
- seen only in the absence of dominant gene (or in males, if it is present on X and has no matching gene on Y)
14
Q
Autosomal dominant diseases
A
- Huntington’s
- Osteogenesis imperfecta
- Marfan’s syndrome
15
Q
Huntington’s
A
- progressive neurological disease
- genetic mutation on 4th chromosome
- abnormal production of huntington protein
- 50/50 chance of inheriting this gene from parent (if present, person has disease)
- symptoms start in 30-40s
- 10-20 yr lifespan after dx
- genetic testing available, but may not want
16
Q
Osteogenesis imperfecta
A
Brittle bone disease
- genetic defect on genes responsible for collagen synthesis
- rare congenital disorder of collagen synthesis
- 25% no family Hx, spontaneous gene mutation
- wide range of presentations: short, thin skin, joint hypermobility
17
Q
OI treatment/management
A
- fracture prevention and control
- positioning and orthosis
- careful handling, PROM without force, family education, swimming, strengthening
- prognosis: varies from relatively normal life span
18
Q
Marfan’s syndrome
A
Disease of connective tissue, typically affecting bones and blood vessels, long limbs, and heart defects
- genetic defect affects structure of protein fibrillin
19
Q
Autosomal recessive
A
- Both parents pass on defective gene: homozygous (2 recessive genes) child has genotype and phenotype
- one parent passes on 1 defective gene: heterozygous child who is a carrier (with genotype) but without signs (phenotype)
- spinal muscular atrophy - sickle cell anemia - cystic fibrosis
20
Q
Spinal muscular atrophy
A
- 1/50 carries
- 2nd most fatal autosomal recessive disorder (after cystic fibrosis)
- 1/15000 live births
- chromosome #5 gene deletion
- degeneration of anterior horn cells
- progressive atrophy of skeletal muscles and respiratory insufficiency / hypoventilation
21
Q
SMA management
A
Dx: muscle biopsy, electromyogram
- treatment: symptomatic and preventive
- pulmonary infection, orthopedic problems, feeding, scoliosis
- prognosis: varies depending upon onset, death 2-12 years later
- *therapy: positioning, head and trunk control, standing, and aquatic therapy
22
Q
Cystic fibrosis
A
- most common genetic inherited disease in the US
- disease of pancreas that leads to altered production by mucous membranes
- defective gene and protein on chromosome #7
23
Q
Sickle cell anemia
A
- 1/12 African-Americans carry gene for disease
- disease of RBCs: fucked shape and cant carry oxygen
24
Q
Chromosomal diseases
A
Chromosomes either break or fail to separate during gamete formation
- results in abnormal placement of part of the chromosome, altered structure, or an abnormal number of chromosomes
- these birth defects are more common when the mother is over the age of 35
- NOT inherited (spontaneous, random change)
25
Trisomy
- nondisjunction occurs
- chromosome pair doesn’t separate during gamete formation
- 3 chromosomes, so 47 total
- trisomy 21 = downs
- trisomy 18 or 13 are high mortality rate within 1st year
26
Monosomy
Turner’s syndrome
- affects only females
- female only has one X
- failure of ovaries and other sex organs to mature (sterile)
- cardiovascular defects
- dwarfism
- webbed neck (loose folds of skin)
27
Single gene disorders
A disorder that is caused by 1 abnormal gene
- result of genetic mutation, change in 1 gene in reproductive cells, then mutation is passed on to future generations
- 1/200 births
- X linked, recessive and dominant disorders
- color blindness - cystic fibrosis
28
X linked dominant disorders
- inherited dominant allele carried on X chromosome
- males and females can be affected
- mutation of affected X chromosome appears constricted or broken
- fragile X syndrome
29
Fragile X syndrome
- very rare
- laundry list
- Y genes do not exist to cover or replace genes on X
- affects dudes mostly
30
X linked recessive traits
- a trait transmitted by a gene located on the X chromosome; also called sex-linked
- sex-linked disorders are typically carried by the X/female sex chromosome
- recessive genes, but lack matching normal gene on Y chromosome
31
Why do men get X-linked diseases more than women?
- X and Y chromosomes do not carry the same info
- X tends to carry more genetic info than Y chromosomes
- X linked diseases usually occur in males because males have only 1
- a single recessive gene on that X chromosome will cause the disease
32
Muscular dystrophies
- largest and most common group of inherited progressive neuromuscular disorder
- any time in life span
- symmetrical muscle wasting
- 6 types: Becker’s, facioscapulohumeral, limb-girdle, myotonic, muscular dystrophy congénita
- pseudo-hypertrophic (calves) connective tissue and fat deposits
33
Hemophilia
- bleeding disorder, lack of clotting factor, 10 proteins
- signs: excessive bruising, joint bleeding
- knee most frequently involved, synovial hypertrophied
- hemathrosis S&S: tingling, flexion stiffness, swelling, decreased ROM, warmth, pain, protective muscle spasm
- management: factor replacement, RICE, painfree movements, pain medications
34
Genetic disorder
Disease caused by a variation or mutation of a gene
- mutations occur spontaneously or due to environmental factos. Some genetic disorders are inherited
- 20-30% of pediatric hospital admissions
35
Congenital disorder
Any anomaly present at time of birth, regardless of cause (infection, malnutrition, genes, or drug exposure)
36
Spinal bífida
Congenital neural tube defect
- malformation of spine, occurs very early in pregnancy
- forms: oculta (not visible), meningocele, and myelomeningocele (most serious)
37
Meningocele
Saclike cyst outside spine
| - rare neurological deficits
38
Myeloeningocele
Saclike cyst outside spine
| - flaccid or spastic paralysis, B&B incontinence, deformation, hydrocephalus, cognitive limitation
39
Erb’s palsy
Etiology: brachial plexus injury during birth (3 types)
40
Arthrogryposis multiple congénita
Etiology: decreased fetal movement
| - can present as club foot or hip dysplasia
41
Multifactorial disorders
- involve a number of genes combined with environmental factors, localized area
- the interaction of genetic and environmental factos, so can be affected
- heart disease - breast and colon cancer - type 2 diabetes mellitus
42
Phenotype - multiple interactions
- genes
- diet
- environment
- social
- psychological
- allergens
- infection
- exercise
