Ch 10 - Genetics

Question 1

the study of individual genes and their effect on seemingly rare, single gene disorders

Answer 1

Genetics

Question 2

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

Answer 2

genomics

Question 3

What are the implications of shifting to a genomics focus?

Answer 3

cancer research → target drug and tx measurements to know how to they respond across humanity

Question 4

Human genome project findings

Answer 4

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.

Question 5

What is the most efficient, cost effective way to be able to predict genetic disorders?

What does it include?

Answer 5

Accurate family history

Should include history of diseases, as well as ethnic and cultural background of all blood related relatives for 3 generations

Question 6

Tests for down syndrome & spina bifuda
Tested at 16 weeks
Has a high false positive rate.

Answer 6

MSAFP 4

Question 7

US test for downs syndrome, tests fat fold in the back of the neck.

noninvasive.

Answer 7

Nuchal translucency

Question 8

What are some tests you might consider for someone who is black or jewish?

Answer 8

sickle cell - blacks

Tay Sachs - jews

Question 9

What are some tests you might consider for disorders that are specific to family history? (hint: genetic disorders)

Answer 9

trisomy’s

cystic fibrosis (autosomal recessive gene - both parents must have for children to be affected)

Huntington’s

Question 10

The different ways a test can be done

Answer 10

• Blood
• US
• IVF
• CVS - chorionic villus sampling - sample of amniotic tissue
• Amniotic fluid (toward end of 2nd trimester, but w/in enough time to terminate before viability)

Question 11

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

Answer 11

PKU - phenylketonuria

If you have too much phenolyline, it may result in neurologic/cognitive delays, but is manageable if caught early

Question 12

BRCA1 & BRCA2

Answer 12

breast cancer screen

Question 13

How many chromosomes do both sperm & egg contribute each?

Answer 13

23

22 autosomes + 1 sex chromosome

Question 14

contributes most of the traits & characteristics

Answer 14

autosomes

Question 15

Which sex chromosome determines the sex of the baby?

Answer 15

father’s

Question 16

chromosomal disorder caused by missing/incomplete X chromosome.

happens in females

causes short stature, delayed puberty, infertility, …. etc

many will miscarry spontaneously

Answer 16

turners (X-linked) - also called gonadal dysgenesis

Most will lead normal lives

Question 17

chromosomal disorder caused by a male w/ an extra X chromosome

causes infertility, small testicles, mild intellectual disability, gynecomastia

Answer 17

Klinefelter syndrome (Y linked)

Most will lead normal lives

Question 18

What is the major cause of reproductive loss?

Answer 18

chromosomal anomalies

Question 19

What % of pregnancies w/ chromosomal anomalies result in spontaneous abortion?
When do they generally occur?

Answer 19

60%

Generally before the first 12 weeks of pregnancy

Question 20

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.

Answer 20

Aneuploidy

Question 21

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

Answer 21

polyploidy

Question 22

Most common type of chromosomal abnormality, responsible for most genetic cases of mental retardation

Answer 22

Aneuploidy

Question 23

the result of a union between normal gamete and one with an EXTRA chromosome

Answer 23

trisomy

Question 24

the result of a union between normal gamete and one MISSING a chromosome

Answer 24

monosomy

Question 25

The most common autosomal aneuploid conditions involve ...

Answer 25

trisomies

Question 26

When do most trisomies occur?

Answer 26

oogenesis

Question 27

What factor in the woman will increase the risk of trisomies?

Answer 27

advanced maternal age. More risk the older the mom is.

Question 28

trisomy 21

Answer 28

down syndrome

Question 29

trisomy 13

Answer 29

patau syndrome

Question 30

trisomy 18

Answer 30

edward's syndrome

Question 31

what percentage of newborns w/ trisomy 13 & 18 are born stillborn?

Answer 31

50%

Question 32

``` What is this describing: wide spaced eyes low nasal bridge no neck low set ears simian crease in hand ```

Answer 32

Down syndrome

Question 33

ways in which abnormalities of chromosome structure occur:

Answer 33

Translocation - EXCHANGE of chromosomal material between two chromosomes Deletion - loss of chromosomal material and partial monosomy for the chromosome involved. Often associated with retardation (both cognitive and psychomotor) and organ malformation Inversions - portion of the chromosome has been REARRANGED in reverse order.

Question 34

*Combination of genetic and environmental factors* Examples would be neural tube defects and cleft lip/palate

Answer 34

multifactorial - tends to run in families, but not as easily inheritable

Question 35

*One gene controls a particular disease or disorder.* Much more common than chromosomal abnormalities. Include things like autosomal dominant, autosomal recessive, and X linked dominant and recessive modes of inheritance

Answer 35

Unifactorial risk and recurrence are HIGH

Question 36

Only one copy of a variant allele needed for phenotypic expression- *only one parent needs to pass the gene on for expression of the trait.*

Answer 36

Autosomal Dominant Inheritance

Question 37

Need a gene from each parent in order to have the disorder show up People who only have one gene passed on are known as carriers May skip generations If affected individual reproduces, all children will at least be carriers

Answer 37

Autosomal Recessive Inheritance

Question 38

A mode of genetic inheritance by which a dominant gene is carried on the X chromosome. No male to male transmission (XX/XY)

Answer 38

X Linked Dominant Inheritance

Question 39

Abnormal genes carried on X chromosome Females can be hetero or homozygous because they have two X chromosomes Males said to be hemizygous because they only have one X chromosome

Answer 39

X Linked Recessive Inheritance

Question 40

PKU Cystic fibrosis sickle cell dz

Answer 40

Autosomal Recessive Inheritance

Question 41

huntington dz Marfan syndrome Achondroplasia Factor V Leiden

Answer 41

Autosomal Dominant Inheritance

Question 42

Hemophelia Color blindness Duchenne muscular dystrophy Fragile X syndrome

Answer 42

X Linked Recessive Inheritance

Question 43

Hypophosphatmic Rickets

Answer 43

X Linked Dominant Inheritance

Question 44

Helps individuals and families to understand the medical facts surrounding a diagnosis, including probable course of the disorder and the available management Choosing a course of action that seems to them appropriate in view of their risk, family goals, and ethical and religious standards and act in accordance with that decision Make the best possible adjustment to the disorder in an affected family member or to the risk of recurrence of the disorder

Answer 44

genetic counseling

Question 45

Ethical, legal, and social implications of genetic testing

Answer 45

not 100% accurate costly & not always covered by insurance patient confidentiality - obligation to pass on info about genetic disorders to other family members cultural values (IVF)