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פידס > GENETICS > Flashcards

GENETICS Flashcards

0
Q

46XXdel(14)(q23)

A

female
46 chromosomes
deletion of chromosome 14 on the long arm at band 23

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1
Q

Chromosomes

short vs long arm

A

contain genetic code for making proteins for cellular structure and enzyme rxns

46 chromosomes: 23 pairs
= 22 autosome pairs
=1 pair sex

Pair of chromatids joined by a centromere
Short arm = P (on the top)
Long arm = Q (on the bottom)

Died bands: the higher numbers further from the centromere

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2
Q

47, XY, +21

A

male
47 chromosomes
extra 21

TRISOMY 21: DOWNS SYNDROME

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3
Q

Chromosomal Abnormalities

two types

A

Numerical Abnormalities
Structural Abnormalities

–can be inherited or de-novo
in de novo neither parent has the abnormal gene, it spontaneously occurs

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4
Q

Numerical Abnormalities

A

Non Disjunction Error:
entire chromosome/ sister chromatids, do not separate to different cells–
occurs most in older cells
occurs during meiosis or mitosis

anueuploidy: ( a condition in which the number of chromosomes in the nucleus of a cell is not an exact multiple of the monoploid number of a particular species.)
monosomy: missing chromosomes
trisomy: extra chromosomes
* downs syndrome, turner syndrome, kleinfelter syndrome

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5
Q

Structural Abnormalities (4)

A

Deletions: portion of entire chromosome is missing

Duplications: portion of chromosome is duplicated resulting in extra genetic material

Translocations: portion of one chromosome is transferred to another chromosome

Inversions: a portion of the chromosome has broken off and turned upside down and reattached, causing the genetic material to be inverted

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6
Q

Deletions:

A

portion of entire chromosome is missing

cri cu chat (de novo chromosome 5)

prader will syndrome (de novo paternal deletion chromosome 15)

angleman syndrome (de novo maternal deletion chromosome 15)

williams syndrom (de novo chromosome 7)

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7
Q

Duplications:

A

portion of chromosome is duplicated resulting in extra genetic material

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8
Q

Translocations:

A

portion of one chromosome is transferred to another chromosome

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9
Q

Inversions:

A

a portion of the chromosome has broken off and turned upside down and reattached, causing the genetic material to be inverted

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10
Q

GDD

A

global developmental delay

delay in achieving 2 or more developmental milestones

motor
speech
cognition
social 
emotional
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11
Q

Intellectual Disability

what is MR

A

mental retardation

IQ of 70-75 or less

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12
Q

Mild MR

A

50-70

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13
Q

Moderate MR

A

40-50

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14
Q

Severe MR

A

20-40

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15
Q

Profound MR

A

below 20

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16
Q

Lead Poisoning

  • what it causes
  • what AAP says to check up
A

no obvious symptoms

can cause GDD

AAP says screenings well check ups:
9-12 months and then again at 24 months

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17
Q

Cognitive Impairments (6)

A

1) able to learn fewer number of things
2) need more repetitions for learning to occur
3) slower response time

4) difficulty generalizing skills from one environment to another
perform skill in PR but not in natural environment

5) greater difficulty maintaining skills that are practiced
6) have limited repertoire of responses

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18
Q

Autosomal Trisomy

A

nondisjunction error during gametogenesis: meiosis

associated with advanced maternal age

Trisomy 21: extra copy if chromosome 21: Downs Syndrome

Trisomy 18 (Edwards syndrome)

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19
Q

Sex Chromosome Aneuploidy

name 2

cause

A

CAUSE: non disjunction error

  1. Turner’s Syndrome (X_): 45X: one less X chromosome or partially missing
  2. Kleinfelter Syndrome (XXY): 47XXY: extra chromosome
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20
Q

Turner’s Syndrome

A

ONLY FEMALES AFFECTED

1) short stature
2) DYSMORPHIC FEATURES: mishaped ears, short webbed neck, puffy hands and feet
3) HTN
4) hypothyroid: tired, delayed growth/height, heavy dry skin, brittle nails
5) lack estrogen: osteoporosis
6) kidney abnormalities (one kidney so avoid collisions/contact sports)
7) delayed/absent sexual development
8) frequent middle ear infections–balance/vestibular, hearing affects development of speech
9) visual spacial difficulties, difficulty judging distance and depth perception difficulties (crossing street, stairs)

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21
Q

Kleinfelter Syndrome

A

MALES ONLY

learning disabilities

speech and language delays

poor coordination

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22
Q

online Prader-Willi syndrome

A

Prader-Willi syndrome is a complex genetic condition that affects many parts of the body. In infancy, this condition is characterized by weak muscle tone (hypotonia), feeding difficulties, poor growth, and delayed development. Beginning in childhood, affected individuals develop an insatiable appetite, which leads to chronic overeating (hyperphagia) and obesity. Some people with Prader-Willi syndrome, particularly those with obesity, also develop type 2 diabetes mellitus (the most common form of diabetes).
People with Prader-Willi syndrome typically have mild to moderate intellectual impairment and learning disabilities. Behavioral problems are common, including temper outbursts, stubbornness, and compulsive behavior such as picking at the skin. Sleep abnormalities can also occur. Additional features of this condition include distinctive facial features such as a narrow forehead, almond-shaped eyes, and a triangular mouth; short stature; and small hands and feet. Some people with Prader-Willi syndrome have unusually fair skin and light-colored hair. Both affected males and affected females have underdeveloped genitals. Puberty is delayed or incomplete, and most affected individuals are unable to have children (infertile).

23
Q

Structural Abnormalities

4 syndromes

A

cri cu chat (de novo chromosome 5)

prader willi syndrome (de novo paternal deletion chromosome 15)

anglemand syndrome (de novo maternal deletion chromosome 15)

williams syndrom (de novo chromosome 7)

24
Q

Hypotonia

what diseases associated with it

A

genetic syndromes

neurological diseases

endocrine

metabolic diseases

down synrome

cerebral palsy

spinal muscle atrophy

**hypotonia of unknown origin

25
Q

Characteristics of Hypotonia

A

1) decreased strength
2) delayed motor sill development
3) poor attention/motivation
4) decreased activity tolerance
5) hypermobile joints (increased flexibility)
6) lean on supports (rounded shoulders)

26
Q

Failure To Thrive

A

weight consistently below 3rd-5th percentile for age

progressive loss of weight to below 3rd to 5th percentile

decrease in percentile rank for height and weight in a short period

27
Q

Conditions associated with failure to thrive

A

1) AIDS
2) CF
3) Hypothyroid
4) Fetal Alcohol Syndrome
5) Neurologic Impairment
6) Gastrointestinal Disorder: GERD
7) Cardiovascular disease
8) Renal disease
9) *poor parenting
10) prematurity

28
Q

Cri-Du-Chat

online

A

Cri-du-chat (cat’s cry) syndrome, also known as 5p- (5p minus) syndrome, is a chromosomal condition that results when a piece of chromosome 5 is missing. Infants with this condition often have a high-pitched cry that sounds like that of a cat. The disorder is characterized by intellectual disability and delayed development, small head size (microcephaly), low birth weight, and weak muscle tone (hypotonia) in infancy. Affected individuals also have distinctive facial features, including widely set eyes (hypertelorism), low-set ears, a small jaw, and a rounded face. Some children with cri-du-chat syndrome are born with a heart defect.

29
Q

Cri-Du-Chat

how it happens

what sx

A

cri cu chat (de novo chromosome 5)

cat like cry

1) LBW
2) Failure to Thrive (suck/swallow imbalance)

3) Dysmorphic features: large mouth, microcephally

4) strabismus
5) hyotonia
6) congenital heart defect
7) scoliosis

8) GDD
9) MR moderate to severe
10) self injurous behavior (bang head, self biting, pull hair out)

30
Q

Prader Willi Syndrome

A

1) hypotonia
2) obesity– lack normal hunger and satiety cues, low metabolic rate
3) strabismus

4) dysmorphic: short, small hands and feet, narrow face

5) respiratory difficulties
6) sleep apnea, daytime sleepiness
7) poor suck/swallow = feeding difficulties/failure to thrive

8) MR: low to moderate, some still have normal intelligence
9) GDDL average motor milestone acquisition twice the typical age –walk at 2

10 ) poor fine and gross motor coordination

11) behavioral issues: stubborn, tantrums, strong need for routines, physical aggression
12) scoliosis
13) developmental dysplasia hips (DDH) birth hips normal over time a problem develops

31
Q

Angelman Syndrome

A

angleman syndrome (de novo maternal deletion chromosome 15)

1) hypotonia

2) tremors, jerky movements
3) seizures
4) scoliosis
5) wide base ataxic gait

6) dysmorphic: microcephalic, large mouth
7) expressed language impaired more than receptive (use sign language)
8) GDD

9) intellectual disability
10) ADD/ADHD

11) **inapropriate happy affect with episodes of laughing–telltale sign. SHOWS INTEREST IN PEOPLE-often misdiagnosed as Autism or CP

32
Q

Williams Syndrome

A

williams syndrom (de novo deletion chromosome 7)

1) CV disease: elastin arteriopathy causes aortic and pulmonary stenosis, HTN
2) Radio-ulnar synostosis
3) mild cognitive impairment to normal intelligence, ADHD
4) delayed speech / fine / gross motor delay
5) visual / spacial difficulties

33
Q

Single Gene Disorders

4 types

A

autosomal dominant

autosomal recessive

x linked recessive inheritance

mitochondrial disorders

34
Q

Autosomal Dominant Disorders

3 examples

A

single mutated or abnormal gene from one parent (dominates) overrides the matching normal gene from the other parent

inherited from affected parent

examples

1) Osteogensis Imperfecta
2) Congenital Myotonic Dystrophy
3) Neurofibromatosis (NF1)

35
Q

Neurofibromatosis

NF1

A

gene encodes neurofibromin

neurofibromin tumor suppressor keeps cells from growing and dividing too rapidly or uncontrolled. mutations can not regulate cell growth and divisions

cafe au lait brown or tan pigmented flat spots on skin –appear at birth but may develop later, can be normal brithmark. More than 6 or larger than 15mm

tumor benign or malignant: occur in nerves, develop in adolescence or adulthood

optic glioma age 0-4: vision loss (squinting, involuntary eye movements, decrease visual acuity)

scoliosis/kyphosis

pectus excavatum

learning disabilities: ADHD

poor coordination/clumsy

hypotonia

tibial dysplasia: causes bowing, could reasult in LLD

NF1 is associated with skeletal abnormalities such as short stature, scoliosis, and long bone fx with nonunion
decreased BMD, decreased bone strength, and low muscle mass all which may predispose them to fx and scoliosis (dont do contact sports)

36
Q

online

What is the normal function of the NF1 gene?

A

The NF1 gene provides instructions for making a protein called neurofibromin. This protein is produced in many types of cells, including nerve cells and specialized cells called oligodendrocytes and Schwann cells that surround nerves. These specialized cells form myelin sheaths, which are the fatty coverings that insulate and protect certain nerve cells.
Neurofibromin acts as a tumor suppressor protein. Tumor suppressors normally prevent cells from growing and dividing too rapidly or in an uncontrolled way. This protein appears to prevent cell overgrowth by turning off another protein (called ras) that stimulates cell growth and division.

37
Q

Biomechanical Disorders

A

metabolism errors caused by mechanical enzyme deficiencies

enzyme absent or not functioning properly. can cause neuromotor and or musculoskeletal deficits

  1. PKU
  2. Lysosomal Storage disease
38
Q

Phenylketonuria

A

phenylalanine breakdown

part of newborn screening panel

panel looks for elevated level of metabolites

39
Q

Lysosomal storage disease

A

lysosomal malfunction because of a deficiency of a single enzyme required for lipid or mucopolysaccharide metabolism

this results in acculmolation of undegraded materials within the lysosome

ie tay sach’s, goucher’s

40
Q

Autosomal Recessive Disorders

A

same recessive mutated gene is inherited

typically neither parent is affected, no family hx

ie CF, sickle cell disease, spinal muscle atrophy, and biochemical disorders

41
Q

Sex Linked Disorders

A

x linked recessive

x linked dominant

42
Q

X linked Recessive

A

only males affected

females are carriers

classic family history–affected males and typical females

mom has abnormal gene on her X: 50% chance of passing it

female who inherits an c with a gene for a sex linked disorder usually no sx because has a normal copy x too

males who inherit an x chromosome with a gene for a sex linked disease have no second x to fall back on and therefore have the disease

examples:
Hemophelia
Duchenne Muscular Dystrophy (DMD)

43
Q

Fragile X Syndrome

A

FMR1 gene on the long arm (q) of X chromosome responsible for making a protein needed for brain development– a mutation occurs and proper brain function is disrupted

a small section of the gene code (CGG) repeats itself on a fragile area of the X chromosome

1) hypotonia
2) hyperextensible joints
3) poor coordination
4) impaired balance
5) poor motor planning

6) GDD, walk by age 2, speech and language and motor delays
7) intellectual disability
8) autism spectrum disorder
9) seizures

44
Q

Retts

cause
diagnosis

A

occurs almost exclusively in females

mutation X chromosome: MECP2 Gene

  • MECP2 regulates other proteins needed in brain maturation
  • development normal until MECP2 is needed

Diagnose

  • -blood test for mutation
  • -diagnostic criteria
45
Q

Retts

vs autism

A

retts often misdiagnosed for autism

have autistic like features at an early age that disappear

in retts prefer people to objects and like affection

46
Q

Retts

diagnostic criteria

A

essential diagnostic criteria
1) Normal development until 6-18 months (then regression)

2) normal head circumference at birth then SLOWING rate of head growth at 2-4 months old
3) MR
4) Gait abnormalities
5) STEREOTYPIC HAND MOVEMENTS

loses communication skills and purposeful use of hands and decelerationr of head growth

47
Q

Retts

Stage 1

A

stage is for a few months to a year

At around 6-18 months: subtle slowing of development

  • delays in grow motor
  • less eye contact
48
Q

Retts

Stage 2

A

between age 1-4 years: rapid or gradual loss of acquired skills

1) autistic-like behaviors: lose spoken language and social interaction
2) lose purposeful hand movements: self feeding: instead stereotypic hand movements: wringing, clapping, washing
3) gait abnormalities: unsteady wide based gait, toe walking, ataxia
4) slowed head growth causes microcephaly
5) behavior disturbances
6) tremors

49
Q

Retts

Stage 4

A

reduced mobility

muscle weakness

rigidity spasticity dystonia

neuromuscular scoliosis 75% age 13–physical exam, educate parents

cognition, communication and hand skills do not usually decline

osteoporosis risk high risk for femoral fx

life expectency about 40 yrs

50
Q

Retts

Stage 3

A

2-10 years

(many stay in this stage for most of their lives)

1) apraxia
2) seizures
3) communication skills may improve
4) motor difficulties
5) intellectual disability (moderate to severe)
6) breath holding, hyperventilation breath holding

51
Q

Mitochondrial Disorders

A

alterations of mitochondrial DNA inherited from MOM

mtDNA codes polypeptides involved with oxidative phosphorylation

can only be transmitted by mom – zygote gets all its mitochondria from the egg

affect CNS and MUSCLE–have large amounts of mitochondria

CLINICAL FEATURES
1) myopathies generalized weakness, decreased balance

2) exercise intolerance
3) encephalopathy
4) retinal degeneration

53
Q

Multifactorial Disorders

A

combination of genetic and environmental factors

the interaction of genetics and environment can result in birth defects

ie cleft palate

and adult onset disorders

ie cancer

54
Q

common characteristics of genetic syndromes

A

hypotonia

failure to thrive

strabismus

GDD: delayed in developmental milestones: all, motor, learning…

microcephalic

55
Q

Retts 4 stages

A
  1. start with normal development until 6-18 months

2 Rapid destructive: . 6-18 months: slow, regress, lose skills, head becomes microcephalic

  1. preschool to school age: apraxia, seizures, communication skills may improve, motor difficulties, intellectual disability (moderate to severe), breath holding, hyperventilation breath holding , motor deterioration
  2. motor deterioration

פידס (13 decks)

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