GENETICS

Question 0

46XXdel(14)(q23)

Answer 0

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

Question 1

Chromosomes

short vs long arm

Answer 1

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

Question 2

47, XY, +21

Answer 2

male
47 chromosomes
extra 21

TRISOMY 21: DOWNS SYNDROME

Question 3

Chromosomal Abnormalities

two types

Answer 3

Numerical Abnormalities
Structural Abnormalities

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

Question 4

Numerical Abnormalities

Answer 4

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

Question 5

Structural Abnormalities (4)

Answer 5

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

Question 6

Deletions:

Answer 6

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)

Question 7

Duplications:

Answer 7

portion of chromosome is duplicated resulting in extra genetic material

Question 8

Translocations:

Answer 8

portion of one chromosome is transferred to another chromosome

Question 9

Inversions:

Answer 9

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

Question 10

GDD

Answer 10

global developmental delay

delay in achieving 2 or more developmental milestones

motor
speech
cognition
social 
emotional

Question 11

Intellectual Disability

what is MR

Answer 11

mental retardation

IQ of 70-75 or less

Question 12

Mild MR

Answer 12

50-70

Question 13

Moderate MR

Answer 13

40-50

Question 14

Severe MR

Answer 14

20-40

Question 15

Profound MR

Answer 15

below 20

Question 16

Lead Poisoning

• what it causes
• what AAP says to check up

Answer 16

no obvious symptoms

can cause GDD

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

Question 17

Cognitive Impairments (6)

Answer 17

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

Question 18

Autosomal Trisomy

Answer 18

nondisjunction error during gametogenesis: meiosis

associated with advanced maternal age

Trisomy 21: extra copy if chromosome 21: Downs Syndrome

Trisomy 18 (Edwards syndrome)

Question 19

Sex Chromosome Aneuploidy

name 2

cause

Answer 19

CAUSE: non disjunction error

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

Question 20

Turner’s Syndrome

Answer 20

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)

Question 21

Kleinfelter Syndrome

Answer 21

MALES ONLY

learning disabilities

speech and language delays

poor coordination

Question 22

online Prader-Willi syndrome

Answer 22

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).

Question 23

Structural Abnormalities

4 syndromes

Answer 23

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)

Question 24

Hypotonia what diseases associated with it

Answer 24

genetic syndromes neurological diseases endocrine metabolic diseases down synrome cerebral palsy spinal muscle atrophy ****hypotonia of unknown origin

Question 25

Characteristics of Hypotonia

Answer 25

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)

Question 26

Failure To Thrive

Answer 26

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

Question 27

Conditions associated with failure to thrive

Answer 27

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

Question 28

Cri-Du-Chat online

Answer 28

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.

Question 29

Cri-Du-Chat how it happens what sx

Answer 29

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)

Question 30

Prader Willi Syndrome

Answer 30

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

Question 31

Angelman Syndrome

Answer 31

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

Question 32

Williams Syndrome

Answer 32

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

Question 33

Single Gene Disorders 4 types

Answer 33

autosomal dominant autosomal recessive x linked recessive inheritance mitochondrial disorders

Question 34

Autosomal Dominant Disorders 3 examples

Answer 34

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)

Question 35

Neurofibromatosis NF1

Answer 35

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)

Question 36

online What is the normal function of the NF1 gene?

Answer 36

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.

Question 37

Biomechanical Disorders

Answer 37

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

Question 38

Phenylketonuria

Answer 38

phenylalanine breakdown part of newborn screening panel panel looks for elevated level of metabolites

Question 39

Lysosomal storage disease

Answer 39

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

Question 40

Autosomal Recessive Disorders

Answer 40

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

Question 41

Sex Linked Disorders

Answer 41

x linked recessive x linked dominant

Question 42

X linked Recessive

Answer 42

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)

Question 43

Fragile X Syndrome

Answer 43

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

Question 44

Retts cause diagnosis

Answer 44

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

Question 45

Retts vs autism

Answer 45

retts often misdiagnosed for autism have autistic like features at an early age that disappear in retts prefer people to objects and like affection

Question 46

Retts diagnostic criteria

Answer 46

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

Question 47

Retts Stage 1

Answer 47

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

Question 48

Retts Stage 2

Answer 48

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

Question 49

Retts Stage 4

Answer 49

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

Question 50

Retts Stage 3

Answer 50

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

Question 51

Mitochondrial Disorders

Answer 51

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

Question 53

Multifactorial Disorders

Answer 53

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

Question 54

common characteristics of genetic syndromes

Answer 54

hypotonia failure to thrive strabismus GDD: delayed in developmental milestones: all, motor, learning... microcephalic

Question 55

Retts 4 stages

Answer 55

1. start with normal development until 6-18 months 2 Rapid destructive: . 6-18 months: slow, regress, lose skills, head becomes microcephalic 3. preschool to school age: apraxia, seizures, communication skills may improve, motor difficulties, intellectual disability (moderate to severe), breath holding, hyperventilation breath holding , motor deterioration 4. motor deterioration