genetics / development Flashcards
chromosome
in the nucleus of each cell of our genes
23 pairs
sex chromosome
X or Y
XX is female
XY is male
autosome
one of the numbered chromosomes
NOT a sex chromosome
Arranged largest to smallest, short to long
allele
different versions of a gene
Homozygous
two alleles are the same
heterozygous
two alleles are different
x linked genetics: fathers
Girls will be carriers
boys CANNOT have disease or be carriers
x linked genetics: mothers
50% girls will be carriers
50% of the boys having the DISEASE (cannot be carriers)
Chromosomal abnormalities signs and symptoms
dysmorphic features growth restrictions developmental delay hypotonia cardiac impairment
Down syndrome due to
nondisjunction
translocation
nondisjunction
the paired copy of the chromosome does not separate at cell division
translocation
long arm chromosomes 15,21,22 breaks off and reattaches
Down syndrome
Trisomy 21 (3 copies of chromes 21 in each cell)
1/800 babies in BC
Children with DS tend to have:
identifiable facial features
hypotonia, dec strength, lig laxity
heart defects (40%)
Brain patho features of DS
reduced wt of brain
small convolutions
structural abnormalities in motor cortex
Orthopaedic impairments of DS
dec strength / lig laxity
i.e. Atlanta axial instability (check at 5yrs old, avoid somersaults / horseback riding until checked)
Prader WIlli Syndrome
deletion of chromosome
maybe related to disturbance in hypothalamus
Duchenne Muscular Dystrophy
mutation of single gene on X chromosome
usually in males from mother carriers
X21 fails to produce dystrophin protein
progression symmetric mm wasting
Duchenne muscular dystrophy progression
diagnosis at 4-5yrs old via physical exam, CK levels and genetic testing
Steady progression
S/S of Duchenne
calf pseudohypertrophy
gowers sign
developmental signs
gait
PT management Duchenne
Lifespan approach (early intervention, school age, adult)
Medical management
5 types of muscular dystrophy
beckers congential facioscapulohumeral myotonic emery-dreifus
beckers MD
slowly progressive, has some dystrophin
congenital MD
diagnosed after birth, variable prognosis
facioscapulohumeral MD
rare and affects male/females equally
myotonic MD
most common after DMD, least severe
emery-dreifus MD
humeral, perineal, some facial involvement
T/F spinal muscular atrophy is autosomal recessive disorder
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spinal muscular atrophy
anterior horn degeneration (LMN disease)
Gene deletion, extension of deletion =severity
Types of spinal muscular atrophy
Type 1: wergnig Hoffman (most severe)
Type 2: intermediate form
Type 3: kugelberg
Type 4: adult onset
pathogenesis of spinal muscular atrophy
continuous apopotsis of anterior horn cells
loss of survival motor neurons
impairments of spinal muscular atrophy
hypotonia (dec in function NOT strength)
weakness /fatigue (symmetrical and proximal)
treatment of spinal muscular atrophy
preventative
maintain strength, posture, resp, cardio function
Hemophilia
x linked recessive
severe bleeding disorder
Genetics of hemophilia
if mother is a carrier, boy will have it 50%, and girl will be carrier 50%
T/F if mother is not carrier of hemophilia, but previous child had it, the 2nd child will definitely have it
NO, the chances are extremely LOW
primary hemostasis
immediate response to vascular injury
platelet clot at site
secondary hemostasis
delayed
T/f the defining abnormality of hemophilia is impairment of secondary hemostasis
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hemophilia Type A
factor VIII deficiency (responsible for 80% of hemophilia)
Hemophilia Type B
factor IX deficiency (responsible for 20% of hemophilia)
Severe hemophilia major issues
+++ venous access, need for prophylaxis, risk of inhibitor
10-20 bleeds/year
moderate hemophilia major issues
+ venous access, need for prophylaxis, risk of inhibitor
1-3 bleeds/year
mild hemophilia major issues
DDAVPchallenge for hemophilia A
<1 bleed/year
can hemophilia patient exercise
yes, we educate, assess over time, and exercise once bleed is stable
can kids w hemophilia do sports
yes low risk sports (swimming, golf, tennis, biking)
moderate (soccer, hockey, volleyball) are permitted
High risk (ice hockey, martial arts, football) should be avoided
marfan syndrome is an autosomal dominant disorder T/F
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marfan syndrome
connective tissue disorder Chromosome 15 (fibrillar) is suppose to form elastic fibres and theres a lack of them
Greatest implication of Marfan syndrome
aortic aneurysm
PT management for Marfan syndrome
Strength
exercise prescription and close monitoring
neural tube deficits is multifactorial inheritance T/F
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neural tube deficits
failure of neural tube to close
i.e. spina bifida
where is neural tube deficit most common
lumbar and low thoracic region
what helps neural tube deficit rate decline
folic acid and pre natal screening
ethology of neural tube deficit
genetic
exposure to teratogens
folic acid deficiency
Myelomeningocele is AKA
spina bifida
impairments of myelomeningocele
flacid or spastic paralysis mm weakness/wasting contractures dec/absent reflexes dec/absent proprioception
vert column (kyphosis, scolioses, lordosis, osteoporosis)
rectal/bladder incontinence
T/F spina bifida can lead to chiari malformation
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T/F cerebral palsy is a progressive lesion of the brain that occurs before age of 2
F - its NON progressive
Cerebral palsy
disorder of movement and posture
5 co morbidies of Cerebral palsy
hearing/speech deficit seizures scoliosis hip dislocation mental retardation
why has CP increased
inc in pre mature birth survival
advancing maternal age
more vitro fertilization
causes of CP
normal birth weight children: 80% because of factors before birth
low birth weight children: don’t know when the brain damage occurs
T/F any prenatal, perinatal or post natal condition that results in anoxia hemorrhage or brain damage is diagnosed as CP
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diagnosis of CP
registry
hip surveillance
Risk factors associated with Cp pre natal
maternal: infection, diabetes, malnutrition, thyroid, seizures
abnormal placental attachment
risk factors associated with CP perinatal
prematurity
low birth weight
low Apgar score
prolapsed umbilical cord
risk factors with post natal CP
neonatal infection brain tumour CVA anoxia environmental toxis
does having multiple risk factors lead to CP
no
Prenatal causes Cp first/second trimester
brain development disorder
prenatal causes CP early third trimester
peri-ventricular leukomalacia
intraventricular hemorrhage
prenatal causes CP late third trimester
basal ganglia / thalamic lesions
infarcts in middle cerebral artery
perinatal causes of CP
birth asphyxia
birth trauma
post natal causes of CP
stroke
meningitis /encephalitis
brain tumours
near drowning
periventricular leukomalacia
small holes in brain around ventricles due to death of small areas of brain tissue
most common ischemic brain injury in pre mature infants:
periventricular leukomalacia
increased risk for periventricular leukomalacia if:
26-34 weeks gestation
small for gestational age (<3.3lbs)
rupture of membranes, preterm labour
can PVL happen to term babies
yes, could have severe quadriplegia /learning difficulties / epilepsy
PVL diagnosis
ultrasound
cystic changes
when do paediatric strokes occur
90% happen in first week of life
T/F first week of life is your highest risk for stroke across lifespan
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perinatal stroke sign
seizure
perinatal stroke which after involved
middle cerebral
risk factors perinatal stroke
pre-eclampsia
ruptured membranes
bleeding
diabetes
perinatal stroke possible causes
thormbi from placenta
congenital heart disease
dehydration
do adult strokes or perinatal strokes have better outcome
perinatal
Gross motor function classification system
1-5
1 - speed, balance impaired
2 - railing for stairs, uneven surfaces and crowds are hard
3 - assistive mobility device but could be out of chair
4 - wheeled mobility
5- all areas motor function limited. not independent
