USMLE genetics Flashcards

Terms Definitions
thalassemia
1
AR
hemophilia
1
X linked
Inheritance of obesity
polygenic
XXY =
Klinefelter syndrome
ocular albinism
1
X linked
Inheritance of cleft lip/palate
polygenic
Inheritance of G6PD defeciency
X-linked
Inheritance of Bruton agammaglobulinemia
X-linked
Trisomy 13 =
Patau syndrome
Lysosomal storage Dz:

progressive neurodegeneration, hepatosplenomegaly, cherry-spot on macula

Enzyme?
Niemann-Pick

(Sphingomyelinase)
- MR
+ cloudy cornea
Scheie's
CNS neurons, oligodendrocytes, astrocytes are derived from which germ layer?
neuroectoderm
MR, microcephaly, cerebral calcifications, blindness and chorioretinitis, and hepatosplenomegaly are associated with what fetal infection?
CMV
Inheritance of Marfan sydrome
autosomal dominant
Inheritance of neural tube defects
polygenic
Inheritance of childhood/infantile polycystic kidney disease
autosomal recessive
Inheritance of myotonic dystrophy
autosomal dominant
Familial Dyslipidemia type:

Increased VLDL only
(high blood TG)

pathology?
Type IV

(hypertriglyceridemia)

Hepatic overproduction of VLDL
Familial Dyslipidemia type:

Inc Chylomicrons only

pathology?
Type I

(hyperchylomiconemia)

Lipoprotein Lipase deficiency
Gaucher's disease
inheritance, deficient enzyme, accumulated substrate, findings
AR
most common
def- B-glucocerebrosidase
acc- glucocerebroside
hepatosplenomegaly, aseptic necrosis of femur
gouchers cells- crinkled tissue paper
huntingtons disease
5
AD
depression, choreiform movements, dimentia
caudate atrophy
CAG repeats
anticipation
MR, microcephaly, craniofacial defects, and nail and digital hypoplasia can result from in utero exposure to what anticonvulsant?
phenytoin (dilantin)
Turner syndrom =
XO instead of XX
Child with congenital cataracts and neonatal sepsis should be screened for
galactosemia
Definition:

when the cells in the body have a different genetic make-up (such as random X inactivation in females)
Mosaicism
Definition:

severity of Dz worsens or age of onset of dz is earlier in succeeding generations

(example)
Anticipation

(Huntingtons)
Familial Dyslipidemia type:

Increased LDL and VLDL

pathology?
Type IIb

(combined hyperlipidemia)

Hepatic overproduction of LDL
NF 2
5
AD
bilateral acoustic neuroma
ch 22
no lisch nodules or CNS tumors
merlin protein mutation
metachromatic leukodystrophy
inheritance, deficient enzyme, accumulated substrate, findings
AR
def- arylsulfatase A
acc- cerebrosid sulfate
demyelination of axons, ataxia
DiGEORGE Syndrome

DEFECT
CLINICAL PRESENTATION
22q11 deletion.
[CATCH-22]

THYMIC APLASIA → T-cell deficiency
HypO-CALCEMIA 2° to PARATHYROID APLASIA
CARDIAC defects
uniparental disomy for chromosome 15 can cause what syndrome?
angelman
thyroid, cricoid, arytenoid, coniculate, and cuneiform cartilages are derivatives of which branchial arches?
branchial arches 4-6
the spleen arises from dorsal mesentery but is supplied by artery of which gut?
foregut
congenital deafness is associated with in utero exposure to what virus?
rubella
what other malformation is associated with exstrophy of the bladder?
epispadias
MR, hyperphagia, and hypogonadism are characteristics of what congenital syndrome?
Prader-Willi
Inheritance of mucopolysaccharidoses
autosomal recessive (except for Hunter's which is x-linked)
Tall thin man with microtestes, sterility and mildly decreased IQ =
Klinefelter syndrome
Autosomal Dominant Dz:

cafe-au-lait spots, neural tumors, pigmented iris hamartomas, scoliosis
Neurofibromatosis Type 1

(Von Recklinghausen Dz)

(chrom 17)
Definition:

hereditary disorders in which differing phenotypes occur depending on whether an abnormal gene is of maternal or paternal origin

(examples)
Genomic Imprinting

(Prader-Willi or Angelman)
Dx:

severe mental retardation, microcephaly, wide-set eyes, low birth weight, round face, unusual cry

genetic problem?
Cri du chat

(deletion: 5p-)
FAP
4
AD
100% chance of colon ca
APC gene- ch 5
after puberty
★ AUTOSOMAL RECESSIVE DISEASES ★
[MATCH the GAPSS]

MUCOPOLYSACCHARIDOSES (except Hunter's)
ARPKD
THALASSEMIAS
CYSTIC FIBROSIS
HEMOCHROMATOSIS
GLYCOGEN STORAGE Dzs
ALBINISM
PHENYLKETONURIA
SICKLE CELL ANAEMIAS
SPHINGOLIPIDOSES (except Fabry's)
TRISOMY 21

CLINICAL PRESENTATION
[DEAD FACTS]

Dumb - Mental retardation
EPICANTHAL FOLDS
ALZHEIMER'S Dz - early
DUODENAL ATRESIA

FLAT facies
ALL - ↑ risk (acute lymphoblastic leukemia)
Congenital heart dz (usu SEPTUM PRIMUM-type ASD)
TOE GAP 1st-2nd
SIMIAN CREASE
what is incresed in combined hyperlipidemia?
LDL, VLDL
what is pleiotropy?
single mutation exerts multiple effects
chances of achondroplasia increase with what?
increasing paternal age
people with Down syndrome are at increased risk for developing what leukemia?
ALL
Male patient with large testes and mental retardation likely has
Fragile X
Cri-du-chat =
Deletion of short arm of chromosome 5
Dx:

male w/ Atrophic testes, Tall stature, Gynecomastia, decreased testosterone, increased pituitary gonadotropins, male infertility

genetic problem?
Klinefelter syndrome

(maternal meiotic nondisjunction)

[Kline felt her TAG him]
hunters syndrome
inheritance, deficient enzyme, accumulated substrate, findings
X linked
mild hurler's + aggressive behavior
def- iduronate sulfatase
acc- heparan sulfate, dermatan sulfate
If in HARDY-WEINBERG EQUILIBRIUM

ALLELE PREVALENCE
p + q = 1
DUCHENNE'S MUSCULAR DYSTROPHY


DEFECT
Mode of INHERITANCE
DYSTROPHIN helps ANCHOR SKELETAL + CARDIAC mm fibers

DEFECT: (X-linked RECESSIVE)
X-linked FRAME SHIFT mutation
→ DYSTROPHIN (DMD) gene DELETION
→ ACCELERATED MM BREAKDOWN


DYSTROPHIN gene = LONGEST known human gene
→ ⇈susceptible to mutation
MARFAN'S SYNDROME

MODE of INHERITANCE
DEFECT
CLINICAL PRESENTATION
AUTOSOMAL DOMINANT
- FIBRILLIN gene mutation.

Clinical: (+ pectus EXCAVATUM)
[MARFAN'S]
-- MITRAL VALVE Prolapse
-- Ao Incompetence + ANEURYSMS d/t cystic medial Ao necrosis
-- Retinal detachment
-- FIBRILLIN gene mutation
-- ARACHNODACTYLY (= tapering fingers + toes)
-- Neg Nitroprusside test (vs homocystinuria)
-- SUBLUX LENS
CYSTIC FIBROSIS

MODE of INHERITANCE
DEFECT
AUTOSOMAL RECESSIVE
⁂ Most common lethal genetic dz in Caucasians

CFTR channel actively
- SECRETES Cl⁻ in LUNGS + GIT
- REABSORBS Cl⁻ from SWEAT

DEFECT:
- Deletion of Phe at position 508 in CFTR gene on Chr 7.
→ Abn PROTEIN FOLDING
→ CFTR Cl⁻ channel DEGRADED ā reaching plasma membrane
→ Defective Cl⁻ channel → secrete abnormally THICK MUCUS
CN IX supplies the derivatives of which branchial arch?
arch 3
what causes hypospadias?
urethral folds fail to fuse completely, resulting in the external urethral orifice opening onto the ventral surface of the penis
an abnormality in what can produce tirpolar mitoses?
mitotic spindle
this chromosomal defect is the most common of those causing spontaneous abortions
trisomy 16
the recurrent laryngeal branch of CN X supplies which branchial arch?
6th
the embryo is extremely susceptible to teratogens during what span of weeks?
weeks 3-8
by when do genitalia have male/female characteristics?
week 10
A baby with clench fist with index finger overlapping 3rd and 4th fingers =
Edward syndrome
Inheritance of alcoholism is strongest in what family pattern?
From father to son
Main sign of:

X-linked Dominant
All females are affected by father
Which condition has (GAA)x repeats?
(GAA)x repeats = FRIEDRICH'S ATAXIA
FRAGILE X SYNDROME


Mode of INHERITANCE
DEFECT
CLINICAL PRESENTATION
X-linked RECESSIVE defect affecting
FMR1 gene METHYLATION
- a/w Chr breakage
- (CGG)x repeats

Clinical: [MALE]
- MACRO-ORCHIDISM
- MITRAL PROLAPSE
- AUTISM
- LONG FACE, LARGE JAW
- EVERTED EARS
what is the pathophysiology of type V/mixed hypertriglyceridemia?
increased production/decreased clearance of VLDl and chylomicrons
this autosomal dominant disorder is associated with polycystic liver disease, berry aneurysms, mitral valve prolapse
adult polycystic kidney disease
what are symptoms common in Huntington's?
depression, progressive dementia, choreiform movements, caudate atrophy, and decreased levels of GABA and ACh in the brain
name 4 trinucleotide repeat expansion diseases
Huntington's, myotonic dystrophy, Friedrich's ataxia, fragile X (try hunting for my fried eggs)
what are the ANS, DRG, cranial nerves derived from?
neural crest
what 2 components of the placenta are present during week 2?
cytotrophoblast, syncytiotrophoblast
for Hardy-Weinberg - p and q are separate alleles: what does 2pq equal?
heterozygote prevalence
what is an unbalanced translocation?
occurs when non-homologous chromosomes exchange genetic material with a net loss or gain of critical genetic material
what most commonly occurs w/ a polyploidy fetus?

give an example of what polyploidy means
spontaneous abortion

Polyploidy = multiples of 23 chromosomes;
ex) 69 chromosomes in patient
WILLIAMS Syndrome

DEFECT
CLINICAL PRESENTATION
Microdeletion of LONG ARM of chr 7
(includes ELASTIN gene)

CLINICAL: [CDEFGH]
Cardiac abnormalities
Dumb - mental retardation
"ELFIN" facies
FRIENDLY - extremely
GLIB - well developed VERBAL SKILLS
HYPERCALCEMIA d/t ↑ Vit D sensitivity
when are Barr bodies seen?
any individual with 2 X chromosomes
what are the characteristics of neurofibromatosis type II?
bilateral acoustic neuroma, optic pathway gliomas, juvenile cataracts
from what embryologic structure does the coronary sinus originate?
left horn of sinus venosus
5 classic findings in marfan syndrome
- tall
- arachnodactyly
- mitral valve prolapse
- aortic dissection
- lens disslocation
Dx:

mental retardation, long face w/ large jaw, large everted ears, Autism, Macro-orchidism

genetic problem?
Fragile X syndrome

(X-lined defect w/ CGG repeats)

[big testicles = X-rated]
MODES of INHERITANCE

AUTOSOMAL RECESSIVE
- 25% of offspring from 2 CARRIER parents affected
- seen in only 1 generation

Often
- d/t ENZYME DEFICIENCIES
- more SEVERE vs dominant disorders
- Present in CHILDHOOD
What are the
★ TRINUCLEOTIDE EXPANSION DISEASES ★
[Hunting for My Fried X]

HUNTINGton's dz = (CAG)x

MYo[t]onic dystrophy = (CTG)x

FRIEDrich's [a]taxi[a] = (GAA)x

fra[g]ile X syndrome = (CGG)x
where is the break point in Fragile X?
q27.3 on X chromosome
what does a persistent truncus arteriosus result from?
failure of aorticopulmonary system to form
what causes first arch syndrome?
lack of migration of neural crest cells into branchial arch 1 (treacher collins, pierre robin)
what does the ventral pancreatic bud differentiate into?
pancreatic head, uncinate process (lower half of head), and main pancreatic duct
Findings to look for with familial hypercholesterolemia
- high cholesterol (Really high)
- xantomas
- early coronary disease
What is the clinical presentation of trisomy 13?
★ CLEFT LIP / PALATE
★ HOLO-PROSENCEPHALY
★ POLYDACTYLY
Micropthalmia
Microcephaly

Mental retardation - severe
Rocker-bottom feet
Congenital heart disease


DEATH by 1 yo
the smooth part of the right atrium comes from what?
right horn of sinus venosus
the 1st branchial pouch develops into what?
endoderm-lined ear structures - middle ear cavity, eustachian tube, mastoid air cells
what is loss of heterozygosity?
if a patient inherits or develops a mutation in a tumor suppressor gene, the complementary allele must be deleted/mutated before cancer develops - not true for ongogenes
what are the skin findings associated with tuberous sclerosis?
facial lesions - adenoma sebaceum, hypopigmented 'ash leaf' spots
What is the INCIDENCE of trisomy 13?
Trisomy 13 = PATAU'S Syndrome

1 : 15,000
when given to pregnant women, what types of abnormalities can lithium cause in the fetus?
congenital anomalies of the heart and great vessels
the common carotid artery and proximal part of internal carotid are derived from which aortic arch?
3rd (c is 3rd letter of alphabet)
If in HARDY-WEINBERG EQUILIBRIUM

DISEASE PREVALENCE
p² + 2pq + q² = 1

p & q are separate alleles
where is the appendix normally located in relation to the cecum and where is it located when it is retrocecal or retrocolic?
normally found on the medial side of the cecum; retrocecal/colic - located on posterior side of cecum or colon
what is the most severe type of spina bifida?
spina bifida with myeloschisis - open neural tube that lies on surface of back
hemochromatosis
1
AR
ARPKD- infants
AR
Inheritance of hemophilia
X-linked
Klinefelter syndrome =
XXY
Hunter's disease
X linked
mucopolysacchridoses (except hunter's)
1
AR
Inheritance of fragile-X syndrome
X-linked
Inheritance of Fabry disease
X-linked
Inheritance of Hunter disease
X-linked
Inheritance of bipolar disorder
polygenic
Trisomy 18 =
Edward syndrome
Cri-du-Chat
2
congenitalmicrodeletion of ch 5
microcephaly, MR, high pitched crying/mewing, epicanthal folds, cardiac abnormalities
PKU
3
AR
decrease in phenylalanine hydroxylase
MR, growth retardation, eczma, mousy odor
homozygotes with familial hypercholesterolemia have approximately what cholesterol?
700
MR, hydrocephalus, microcephaly, microphthalmia, chorioretinitis, and intracranial calcifications are associated with what nonviral infection?
toxoplasma
Inheritance of tuberous sclerosis
autosomal dominant
Most common presentation of Klinefelter syndrome
infertility
Inheritance of cystic fibrosis
autosomal recessive
Familial Dyslipidemia type:

Increased IDL, VLDL

pathology?
Type III

(dysbetalipoproteinemia)

Altered Apo-E
MCC of Primary Amenorrhea
Turner's syndrome
22q11 deletions
CATCH-22
CATCH 22
cleft palate
abnormal facies
thymic aplasia, T cell deficiency
Cardiac defects
hypocalcemia secondary to parathyroid aplasia
ACHONDROPLASIA

MODE of INHERITANCE
DEFECT
CLINICAL PRESENTATION
AUTOSOMAL DOMINANT

CELL-SIGNALLING defect of FGFr3
(fibroblast growth factor receptor 3).

Clinical:
- DWARFISM (short limbs)
- normal head & trunk size
- a/w PATERNAL AGE
Inheritance of multiple endocrine neoplasias
autosomal dominant
Inheritance of Glycogen storage disease
autosomal recessive
Holoprosencephaly and cleft lip/palate likely =
Patau syndrome
Definition:

disorder when there are at least two X-chromosomes and one or more Y-chromosomes
Klinefelter syndrome
Definition:

one gene has greater then one effect on the individual's phenotype
Pleiotropy
MEN
2
AD, several syndromes
tumors of endocrine glands
ret gene
Krabbes disease
inheritance, deficient enzyme, accumulated substrate, findings
AR
def- galactocerebrosidase
acc- galactocereboside
Lesch Nyhan syndrome
4
X linked
HGPRT deficiency
increased uric acid
tx- allopurinol
LEBER'S HEREDITARY OPTIC NEUROPATHY

MODE of INHERITANCE
PATHOGENESIS
MITOCHONDRIAL INHERITANCE

- Degeneration of RETINAL GANGLION cells + AXONS
→ ACUTE CENTRAL VISION LOSS
& WPW Syndrome
what is type I familial dyslipidemia?
hyperchylomicronemia
what is increased in hereditary spherocytosis?
MCHC
unusually flat abdomen, breathlessness, and cyanosis in a newborn may be signs of what?
congenital diaphragmatic hernia
Baby with hypotonia and transverse palmar crease at birth should be considered for
trisomy 21
Inheritance of adult polycystic kidney disease
autosomal dominant
Equation for Hardy-Weinberg population genetics:

Heterozygote Prevalence
(p and q on separate alleles)
HP = 2pq
Definition:

the normal inactivation of one X chromosome
Lyonization

(creation of Barr Body)
duchenne MD
5
Beckers MD
2
X linked
deletion of dystrophin gene-->muscle breakdown
pseudohypertrophy of calf m. (fibrofatty)
Gower's sign
onset before 5 yrs
Beckers less severe, dystrophin gene mutation
APKD- adult
6
AD
always bilateral
many, large cysts
flank pain, hematuria,
APKD1 gene
berry aneurysms, mitral valve prolapse, liver disease
Prader willi
2
deletion of Paternal allele, maternal imprinted
MR, hyperphagia, obesity, hypogonadism, hypotonia
TUBEROUS SCLEROSIS

MODE of INHERITANCE
CLINICAL PRESENTATION
AUTOSOMAL DOMINANT
- INCOMPLETE penetrance
- VARIABLE presentation

Clinical:
- ADENOMA SEBACEUM (facial lesions)
- 'ASH LEAF SPOTS' (hypopigmented skin)
- Renal ANGIOMYOLIPOMAS + CYSTS
- ↑ASTROCYTOMAS incidence
- CORTICAL + RETINAL HAMARTOMAS
- Cardiac RHABDOMYOMAS (= hamartoma)
- SEIZURES
TRISOMY 21

CAUSES
95% = NON-DISJUNCTION of homologous chr (trisomy 21)
-- a/w ↑MATERNAL AGE

4% = ROBERTSONIAN TRANSLOCATION

1% = DOWN MOSAICISM
-- NO maternal assoc
oxygenated blood reaching the heart via the IVC is diverted through ________ and pumped out the aorta to the head
foramen ovale
in what fashion is spherocytosis inherited?
autosomal dominant
the triad of heart defects, cataracts, and deafness are associated with what viral agent?
rubella
Major features of Patau syndrome
- holoprosencephay
- cleft lip/palate
- mental retardation
- apnea
- deafness
- myelomeningocele
- cardiovascular abnormalities
- rocker bottom feet
Likely inheritance pattern if 25% of children affected
autosomal recessive
MCC of Down's syndrome

what is the other cause?

what is the "Familial form"?
Nondisjunction


(Robertsonian) Translocation
(familial form)
lysosomal storage disease death by 3 yrs
3
Tay Sachs
NP
Krabbes
If in HARDY-WEINBERG EQUILIBRIUM

PREVALENCE of X-LINKED RECESSIVE DISEASE
q in ♂

q² in ♀
CRI-DU-CHAT Syndrome

DEFECT
CLINICAL PRESENTATION
Congenital microdeletion of SHORT ARM of chr 5
(46,XX or XY,5p--)

CLINICAL:
HIGH PITCHED CRYING / mewing ("cry of the cat")
EPICANTHAL folds
MICROCEPHALY

Mental retard-mod-severe
Cardiac abnormalities
ANGELMAN'S Syndrome

DEFECT
CLINICAL PRESENTATION
DELETION of normally active MATERNAL allele on Chr 15 (or uniparental disomy)
& Imprinted paternal genes

Clinical: "HAPPY PUPPET"
- Mental retardation
- SEIZURES
- ATAXIA
- INAPPROPRIATE LAUGHTER
exposure to ACE inhibitors in utero can have what effect on fetus?
renal damage
what is synapsis?
pairing of homologous chromosomes with which meiosis begins
the umbilical arteries become what structure postnatally?
mediaL umbilical ligaments
what do you call inversions that don't include the centromere?
paracentric
arnold-chiari malformation is commonly associated with what other defects?
lumbar meningomyelocele, platybasia, aqueductal stenosis
what germ layer is the adenohypophysis derived from?
surface ectoderm
Girl with coarctation of the aorta and cystic hygroma
Turners syndrome
Which condition has (CTG)x repeats?
(CTG)x repeats = MYO[T]ONIC DYSTROPHY
what is increased in type I/hyperchylomicronemia?
blood TG, cholesterol levels
what is the only lipid storage disease that is X-linked?
Fabry's disease
cafe-au-lait spots, neural tumors, lisch nodules, skeletal disorders (e.g. scoliosis), pheo, and increased tumor susceptibility are associated with what autosomal dominant disease?
neurofibromatosis type I (von Recklinghausen's disease)
the juvenile form of PKD is inherited in what manner?
autosomal recessive
what drug is given to patients with CF to loosen mucous plugs?
n-acetylcysteine
what does the first branchial cleft develop into?
external auditory meatus
what do hammerhead ribozymes do?
catalyze sequence-specific cleavage of RNA phosphodiester bonds due to the secondary structure they form
what is variable expression?
nature and severity of phenotype varies from 1 individual to another
7 classic findings in tuberous sclerosis
- facial angiofibromas (adenoma sebacium)
- seizures
- mental retardation
- CNS hamartomas
- cardia rhabdomycomas
- renal angiomyolipomas
- Hypopigmented skin macules
name two defects that pulmonary hypoplasia can be found in association with
congenital diaphragmatic hernia and bilateral renal agenesis
what is increased in type V/mixed hypertriglyceridemia? what is elevated in blood?
VLDL, chylomicrons, TG, cholesterol
what causes tetralogy of fallot?
abnormal neural crest cell migration such that there is skewed development of the AP septum
what is incomplete penetrance?
not all individuals with a mutant genotype show the mutant phenotype
what is heteroplasmy?
presence of normal as well as mutated mitochondrial DNA
Major features of Edward syndrome
- mental retardation
- small size for age
- small head
- hypoplastic mandible
- low set ears
- clenched fist with overlapping index finger
MODES of INHERITANCE

X-LINKED RECESSIVE
- 50% of SONS from HETEROz MOTHERS
- NO ♂-to-♂ transmission
- Often more SEVERE in ♂

- HETEROz ♀ rarely affected d/t RANDOM INACTIVATION of an X Chr in each cell
Which Chr are MOST OFTEN involved in ROBERTSONIAN TRANSLOCATIONS?
13, 14, 15
21, 22
what is the defect in familial hypercholesterolemia?
defective or absent LDL receptor
what is caudal dysplasia and what causes it?
constellation of syndromes ranging from minor lesions of vertebrae to complete fusion of lower limbs - caused by abnormal gastrulation
when does an omphalocele occur?
when the intestines (midgut loop) fail to return to the abdominal cavity
what cartilage and muscle does branchial arch 3 supply?
greater horn of hyoid, stylopharyngeus (CN IX)
4 classic findings in myotonic dystrophy
- weakness with inability to RELEASE grip
- balding
- cataracts
- mentl retardation
If NONDISJUNCTION of Chr 21 occurs at ANAPHASE II,
what are the chances of OFFSPRING being affected?
50%

25% = n-1
25% = n+1
what does the SVC arise from?
right commmon cardinal vein and right anterior cardinal vein
cleft palate results form the failure of fusion of what?
lateral palatine processes, the nasal septum, and/or median palatine process (formation of secondary palate)
aberrant development of 3rd and 4th pouches results in what syndrome?
DiGeorge's - leads to T-cell deficiency (thymic aplasia) and hypocalcemia (failure of parathyroid development)
what 3 germ layers are present in the third week and what stage is the embryo in?
ectoderm, mesoderm, endoderm; gastrula
where does muscle weakness begin in Duchenne's?
pelvic girdle muscles and progresses superiorly
4 of the major medical risks with Down Syndrome
- ventricular septal defects
- leukemia
- duodenal atresia
- early Alzheimers disease
What is the INCIDENCE of trisomy 21?
Trisomy 21 = DOWN Syndrome

1 : 700
what is the chromosomal abdnormality associated with angelman syndrome
deletion of band q12 on chromosome 15 (found in the mother)
what does the 6th aortic arch give rise to?
proximal part of pulmonary arteries and (on left only) ductus arteriousus
what occurs when the vitelline duct remains open
vitelline fistula - may present with fecal discharge at the umbilicus
what is the role of the allantoic duct?
removes nitrogenous waste (from fetal bladder, like a urethra)
46, XX or XY, 5p-
cri du chat - deletion of short arm of chromosome 5 (cri du has 5 letters)
Rate of Down syndrome by mother's age
- 1/1500 of 16 year old mothers
- 1/25 of 45 year old mothers
branchial arches 4 and 6 are supplied by what nerve?
CN X (4+6=10) (4th arch - superior laryngeal branch, 6th arch - recurrent laryngeal branch)
/ 199
Term:
Definition:
Definition:

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