genetic disease Flashcards
what are the three types of gene mutation
genome mutation
chromosomal mutation
gene variant
what is gene mutation?
loss or gain of an entire chromosome
what is chromosomal mutation
alteration of a segment of chromosomes
what is gene variant
partial or complete deletion of a gene
state the order of specificity of genes
genome -> chromosomes long chain of DNA -> genes (segments of DNA)
What is the typical human genome
44 chromosomes with 23 pairs of chromosomes. 22 pairs will be autosomal and 1 pair of sex chromosomes.
what is meant by hereditary or familiar genes
condition is derived form parents due to a genetic mutation
what is meant by congenital genes
condition is appears at birth. maybe hereditary or can be due to exposure at birth
what are the 5 types of inheritance patterns
- autosomal dominant
- autosomal recessive
- x-linked recessive
- chromosomal
- mixed inheritance
break down the meaning of autosomal dominant
autosomal- the gene in question is located on one of the 44 chromosomes. Not a sex chromosome
dominant- a single copy of the mutated gene is enough to express the gene phenotypically.
what are the three examples for autosomal dominant
- familiar hypercholesterolemia
- marfan syndrome
- osteogenesis imperfecta
what is the mutation of familiar hypercholesterolemia
low density lipoprotein (LDL)
receptor mutation will result in impaired uptake of cholesterol into the cells.
what are the clinical manifestations of familiar hypercholesterolemia
- elevated blood cholesterol levels
-atherosclerosis resulting in cardiovascular disease - death before the age of 30 due to uncontrolled CVD.
What is the mutation in Marfans syndrome
fibrillar-1 gene on the 15 chromosome
fibrillar provides support for production of elastic fibers
what are the clinical manifestations for marfans syndrome
- skeletal: long arms, legs, and fingers
- Eye: Bilateral dislocation of the lens
- cardiovascular: aortic root dilation, leading to aortic insufficiency, myxomatous mitral valve, ascending thoracic aortic aneurysm, aortic dissection
what is the percent breakdown for the presentation of osteogenesis imperfecta?
autosomal dominat 80% of the time
20% is autosomal recessive
what does heterogeneous mean
refers to collagen respresentation in osteogenesis imperfecta is very different.
what is meant by pleiotropic
one gene will influence two phenotypic traits
what is the mutation in osteogenesis imperfecta?
90% of cases are caused by a mutation of the COL1A1 or COL1A2 genes
what two genes encode for type 1 collagen?
COL1A1 and COL1A2
How will an X-ray detect osteogenesis imperfecta?
mild osteopenia
describe the pathophysiology of osteogenesis imperfecta?
disease in type 1 collagen
- a major extracellular protein in the body dermis
can effect: connective tissues int he organs, GI, and Vascular system and bones
what are the S/S of type 1 osteogenesis imperfecta?
fractures- that will decrease after puberty
blue sclera
in adults a short stature
most mild form of OI
What are genetic determinats noticed in type 1 osteogenesis imperfecta?
25% are from new cases
75% are from autosomal dominant
what are the S/S of type 2 osteogenesis imperfecta?
Most severe form
will be present before birth
1. multiple fractures
2. bone deformities
3. significant fragillity of non bony connective tissue
4. blue sclara
5.short limbs
6. small chest
7. soft skull
typically results in death in infancy