Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Medical Genetics > Single Gene Disorders and Complex Inheritance > Flashcards

Single Gene Disorders and Complex Inheritance Flashcards

You may prefer our related Brainscape-certified flashcards:
USMLE® Step 1 flashcards Biology 101 flashcards
1
Q

Mendelian Single Gene Disorders

How are they classified?
How to track?

A

`Classified by location of defect, and mode of transmission

Most are familial, track with pedigree

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a mutation?

A

any permanent change to DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Framshift mutations?

Point Mutations?

A

insertion or deletion of 1 or 2 codons that leads to a shift in the reading frame

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Autosomal Dominant Disorders

Mutation of ?

Describe inheritance patterns: 
   Sex? 
   Parents? 
   Transmission? 
    Offspring? 
    Hetero mating?
A

Mutation of dominant gene on autosome

Patterns: 
   Male/female equal 
    affected usually have 
      affectde parent 
    Unaffected dont transmit 
    Offspring of affected-50%
    75% mating
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Autosomal Dominant Disorder Examples (2)

A

Marfans

Huntington

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Marfans Syndrome

What chromo

A

disorder of CT

tall slender, long appendages

arachnodactyly

skeletal/joint deformities

CV lesions
Fibrillin 1 gene on chromo 15

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Huntington Disease

Chromo affected

A

Neurologial dysfunction

mental deterioration: invol appendage movement

Late acting lethal dominant

chromo 4 has abnormal CAG repeats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Autosomal Recessive Disorders

Mutation of? 
Inheritance pattern: 
   sex? 
   parents? 
   unaffected transmission? 
   Hetero mating?
A

Mutation of recessive gene on autosomes

Male/female equal
disease not apparent in parents of affected
unaffected may transmit
hetero mating- 25% afflicted, 75% not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Autosomal Recessive Disorder Examples (3)

A

Albinism
Phenylketonuria
CF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Albinism

A

Lack of skin, hair, eye pigment

six forms:some have organ effects

one form: lack of tyrosinase
converts tyrosine to
melanin

risk sunburn, skin cancer, impaired vision, photosensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Phenylketonuria

A

inability to metabolzie phemylalanine

inborn error of metabolsim

buildup of dietary phenylalanine in body- affects NS

Irritability, tremorousm slow developing retardation

excess phenylalanine excreted in urine-musty odor

manage with low phenylalanine diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Cystic Fibrosis

A

Most common single gene disorder in caucasian

defective chloride in membrane transporter

productions of abnnormally thick secretions in lungs and pancreas

gene on chromo 7 many diff mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Sex Linked disorders

Aka
most are dom or recessive?
Females may?
Males may?

A

aka X linked disorders
most are x linked recessive

females may express, carry or not carry

males may express or not express

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Sex Linked patterns of inheritance

dependent on?
Affected sex more is?
Affected fathers?
Unaffeted males are?

carrier female has __ chance of affected son.
__ chance of carrier daughter

females affected by

A

Dependent on sex

Affected are usually male

affected fathers transmit to daughters

unaffected male, are unable to carry

carrier female has 50% chance of affected son, 50% chance of carrier daughter

Females affected by: affected or carrier mother to affected father

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Sex linked disorders

Examples:

A

Duchenne MD, Hemphilias A & B, chronic granulomatous disease, agammaglobulinemia, others lol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Hemophilia A

A

Bleeding disorder- lack of factor VIII

bleed easily and profusely

transmitted b/w royal families of europe

queen victoria-first carrier

17
Q

NON MENDELIAN SINGLE GENE DISORDERS:

Fragile X

A

Triple repeat mutations-Fragile X syndrome

LOng repeating sequences of three nucleotides

Fragile X - mental retardation
Constriction on long arm of X contains CGG

Normal: 29 cGG
Fragile x: 230-4k repeats
Premutation: 52-230 repreats

AMPLIFIED DURING OOGENISIES

18
Q

Non Mendelian

Mitochondiral Gene Mutations

A

Passed during cell division

Code for oxidative resp enzymes

dysfunction in tissues with High ATP needs

Tricky inheritance pattern

19
Q

Non mendelian single gene:

Genomic Imprinting?

Prader willi syndrome:

Angelman Syndrome

A

maternal and parental chromosomes are different

Deletion on Paternal 15
mental retardation, short stature, obesity, poor muscle tone, hypogonadisn

Deleteion on MATERNAL 15
mental retardation, ataxia, laugh inappropriately

20
Q

Polygenic Disorders

What are they?

A

Two or more mutant genes act together

Influenced by environment

No clear models of inheritance

range of expression = range of severity

geneticits nightmare

very common

High blood pressure, cancer, DM, cleft lip, heart defects

21
Q

Digenic Retinitis Pigmentosa

A

Simple example of multigenic trait

Causes retinal degen by retinitis pigmentosa

2 rare mutations in 2 diff unlinked genes which are part of the photoreceptor

1 Mutation causes missense the other is null allele

Hetero for either = NO disease

Hetero for BOTH = disease

two mtations cause enough damage to kill photoreceptor cells

22
Q

Venous Thrombosis

Idiopathic cerebral vein thrombosis

A

Gene/gene interaction with enviro influence

Idiopathic cerebral vein thrombosis
young adults- high
mortality
Three factors, 2 genetic/1 enviro

23
Q

Venous Thrombosis

type of genetic error

Variation in 3' UTR of prothrombin gene 
   heterozygotes 3-6x risk 
Oral conreceptive use 
   14-22x risk 
Combined all 3 
   30-150x risk
A

Missense mutation in clotting factor V

Factor V Leiden-FVL
Heterozygotes-7X risk
Homo-80x Risk

24
Q

Hirschsprung Disease (HSCR)

Abnormality of parasympthetic innervation of gut…causes?

Usually isolated to one segment but can be more

Very complex genetics, high risk ratio for siblings

A

NO PERISTALISIS

25
Q

HSCR

Occurs through multiple generations and multiple siblings
what does this suggest

Genes assoc

A

Suggests autosomal dom or recessive

BUT

Males have 2x higher risk = sex linked?

RET gene
EDNRB or EDN3

26
Q

TYPE 1 DIABETES
Onset?
Patho?

Major genetic factor?

CTLA4, PTPN22 also seen

GENETIC FACTORS ALONE DO NOT CAUSE TYPE ! DIABETES

A

In childhood or adolescence

Autoimmune destruction of beta cells in pancreatic islands = no insulin production

MHC locus is MAJOR GENETIC FACTOR

HLA-DR3, HLA-DR4, HLA Class II locus

27
Q

Alzheimer Disease
Fatal Neurodegen disease
Only definitive dx?

A

Most common cause of dementia in elderly

CHrinic progressive loss of memory and other intellicutal functions

Only definitive dx after death—-AMYLOID PLAQUES

28
Q

What are B amyloid plauges

A

B amyloid plaques and neurofibrillary tangles destroy cortical tissue

plaques contain AB peptibe
derived from clevage or normal protien

29
Q

Alzheimers Disease

GENE and GENE LOCATION

What genotype was found 2-3x more in AD patients?

What genotype had earlier onset?

A

APOE Locus- apolopoprotein E

Part of LDL particles
Part of Amyloid plaques

APOE gene maps to CHROMOSOME 19

Genotype with one e4 allele found 2-3x more often in AD patients

HOMOZYGOUS genotype for e4 had earlier onset

30
Q

Mental Illness
affect?
Most severe?

A

4% of humans

Schizo/BPD

31
Q

Schizo

affects ? humans

A

1%

Genetic info supported by twin and family studies

Little certainty as to what genes and alleles predisopse

One exception HIGH PREVELANCE IN CARRIERS OF 22Q11 DELETION WHO HAVE DIGEORGE SYNDROME

32
Q

CAD
some genetic components
FAMILIAL HYPERCHOLESTEOLEMIA

A

Autosomal dom defect of LDL receptor

Multifactorial inheritance

Medical Genetics (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions