Ch 10 - Genetics Flashcards Preview

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Flashcards in Ch 10 - Genetics Deck (45)
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1
Q

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

A

Genetics

2
Q

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

A

genomics

3
Q

What are the implications of shifting to a genomics focus?

A

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

4
Q

Human genome project findings

A

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.

5
Q

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

What does it include?

A

Accurate family history

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

6
Q

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

A

MSAFP 4

7
Q

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

noninvasive.

A

Nuchal translucency

8
Q

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

A

sickle cell - blacks

Tay Sachs - jews

9
Q

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

A

trisomy’s

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

Huntington’s

10
Q

The different ways a test can be done

A
  • 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)
11
Q

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

A

PKU - phenylketonuria

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

12
Q

BRCA1 & BRCA2

A

breast cancer screen

13
Q

How many chromosomes do both sperm & egg contribute each?

A

23

22 autosomes + 1 sex chromosome

14
Q

contributes most of the traits & characteristics

A

autosomes

15
Q

Which sex chromosome determines the sex of the baby?

A

father’s

16
Q

chromosomal disorder caused by missing/incomplete X chromosome.

happens in females

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

many will miscarry spontaneously

A

turners (X-linked) - also called gonadal dysgenesis

Most will lead normal lives

17
Q

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

causes infertility, small testicles, mild intellectual disability, gynecomastia

A

Klinefelter syndrome (Y linked)

Most will lead normal lives

18
Q

What is the major cause of reproductive loss?

A

chromosomal anomalies

19
Q

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

A

60%

Generally before the first 12 weeks of pregnancy

20
Q

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.

A

Aneuploidy

21
Q

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

A

polyploidy

22
Q

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

A

Aneuploidy

23
Q

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

A

trisomy

24
Q

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

A

monosomy

25
Q

The most common autosomal aneuploid conditions involve …

A

trisomies

26
Q

When do most trisomies occur?

A

oogenesis

27
Q

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

A

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

28
Q

trisomy 21

A

down syndrome

29
Q

trisomy 13

A

patau syndrome

30
Q

trisomy 18

A

edward’s syndrome

31
Q

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

A

50%

32
Q
What is this describing:
wide spaced eyes 
low nasal bridge
no neck
low set ears 
simian crease in hand
A

Down syndrome

33
Q

ways in which abnormalities of chromosome structure occur:

A

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.

34
Q

Combination of genetic and environmental factors

Examples would be neural tube defects and cleft lip/palate

A

multifactorial

  • tends to run in families, but not as easily inheritable
35
Q

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

A

Unifactorial

risk and recurrence are HIGH

36
Q

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.

A

Autosomal Dominant Inheritance

37
Q

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

A

Autosomal Recessive Inheritance

38
Q

A mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

No male to male transmission (XX/XY)

A

X Linked Dominant Inheritance

39
Q

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

A

X Linked Recessive Inheritance

40
Q

PKU
Cystic fibrosis
sickle cell dz

A

Autosomal Recessive Inheritance

41
Q

huntington dz
Marfan syndrome
Achondroplasia
Factor V Leiden

A

Autosomal Dominant Inheritance

42
Q

Hemophelia
Color blindness
Duchenne muscular dystrophy
Fragile X syndrome

A

X Linked Recessive Inheritance

43
Q

Hypophosphatmic Rickets

A

X Linked Dominant Inheritance

44
Q

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

A

genetic counseling

45
Q

Ethical, legal, and social implications of genetic testing

A

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)