Flashcards in Ch 10 - Genetics Deck (45)
the study of individual genes and their effect on seemingly rare, single gene disorders
the study of all genes in the human genome together. This includes their interactions with each other and the environment
- genetic material across ethnic, culture, etc
What are the implications of shifting to a genomics focus?
cancer research → target drug and tx measurements to know how to they respond across humanity
Human genome project findings
Human beings are 99.9% equal on the DNA level
Humans do not have more genes than other species. The use of different proteins enables higher functioning at a more differentiated level than in other species.
What is the most efficient, cost effective way to be able to predict genetic disorders?
What does it include?
Accurate family history
Should include history of diseases, as well as ethnic and cultural background of all blood related relatives for 3 generations
Tests for down syndrome & spina bifuda
Tested at 16 weeks
Has a high false positive rate.
US test for downs syndrome, tests fat fold in the back of the neck.
What are some tests you might consider for someone who is black or jewish?
sickle cell - blacks
Tay Sachs - jews
What are some tests you might consider for disorders that are specific to family history? (hint: genetic disorders)
cystic fibrosis (autosomal recessive gene - both parents must have for children to be affected)
The different ways a test can be done
- CVS - chorionic villus sampling - sample of amniotic tissue
- Amniotic fluid (toward end of 2nd trimester, but w/in enough time to terminate before viability)
Screening for genetic disorders and other inborn errors of metabolism while in the hospital
Usually done between 24-48 hrs of birth.
~30 disorders per screening
PKU - phenylketonuria
If you have too much phenolyline, it may result in neurologic/cognitive delays, but is manageable if caught early
BRCA1 & BRCA2
breast cancer screen
How many chromosomes do both sperm & egg contribute each?
22 autosomes + 1 sex chromosome
contributes most of the traits & characteristics
Which sex chromosome determines the sex of the baby?
chromosomal disorder caused by missing/incomplete X chromosome.
happens in females
causes short stature, delayed puberty, infertility, .... etc
many will miscarry spontaneously
turners (X-linked) - also called gonadal dysgenesis
Most will lead normal lives
chromosomal disorder caused by a male w/ an extra X chromosome
causes infertility, small testicles, mild intellectual disability, gynecomastia
Klinefelter syndrome (Y linked)
Most will lead normal lives
What is the major cause of reproductive loss?
What % of pregnancies w/ chromosomal anomalies result in spontaneous abortion?
When do they generally occur?
Generally before the first 12 weeks of pregnancy
an abnormal number of chromosomes within a cell
is a type of chromosomes abnormality
An extra or missing chromosome is a common cause of genetic disorders.
the condition in which a normally diploid cell or organism acquires one or more additional sets of chromosomes.
has 3 or more times the haploid chromosome number
Most common type of chromosomal abnormality, responsible for most genetic cases of mental retardation
the result of a union between normal gamete and one with an EXTRA chromosome
the result of a union between normal gamete and one MISSING a chromosome
The most common autosomal aneuploid conditions involve ...
When do most trisomies occur?
What factor in the woman will increase the risk of trisomies?
advanced maternal age. More risk the older the mom is.