Principles of Development: Body, Limb, and Brain Patterning & Disorders Flashcards

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1
Q

A cell that can give rise to a number of different cell types of the same germ layer, but not that of a different germ layer is:
A. multipotent
B. pluripotent
C. terminally differentiated
D. totipotent
E. unipotent

A

A. multipotent

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2
Q

A cell that is capable of giving rise to all cells of an embryo except the extraembryonic membrane is described as:
A. multipotent
B. pluripotent
C. terminally differentiated
D. totipotent
E. unipotent

A

B. pluripotent

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3
Q

Patients with situs ambiguous are examples of errors in which of the following developmental processes?

A. Anterior-posterior (rostral-caudal) axis determination
B. Dorsoventrical axis determination
C. Left-right axis determination
D. Organogenesis
E. Segmentation

A

C. Left-right axis determination

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4
Q

Which of the following statements about the HOX genes is incorrect?
A. The code for cell surface receptors necessary for normal development
B. They demonstrate spatial colinearity with the developing embryo
C. They demonstrate temporal colinearity with the developing embryo
D. They play a role in determining the fate of cells in a developing embryo
E. They play a role in the positional identity of cell sin a developing embryo

A

A. The code for cell surface receptors necessary for normal development

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5
Q

A patient is found to have asplenia and two tri-lobed lungs. Which one of hte following diagnoses is most appropriate?
A. Absent spleen syndrome
B. Left isomerism
C. Right isomerism
D. Sinus inversus totalis
E. Sinus solitus

A

C. Right isomerism

  • Spleen is on the left side of your body, so if missing you have right isomerism
  • right lung is normally trilobed, so if both trilobed must be right isomerism
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6
Q

Which oen of the following body patterning follows the so called “Hox code”?
A. Dorsal-ventral patterning of the CNS
B. Dorsal-ventral patterning of the limbs
C. Left-right patterning
D. Proximal-distal patterning of the lib
E. Segmentation along the AP axis

A

E. Segmentation along the AP axis

The Hox code is important in specifying the locations of limb bud development relative to the location on the AP axis on either side of the early embryo.

In humans, the anterior digit is the thumb, and the posterior digit is the fifth finger.

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7
Q

Segmentation is determined by…
A. cadherin-mediated cell movement
B. cilia-mediated direction of fluid flow
C. DNA methylation and histone diacetylation
D. differential ratios of morphogen-gradient-mediated transcriptional regulation
E. Ubiquitin-mediated processes

A

D. differential ratios of morphogen-gradient-mediated transcriptional regulation

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8
Q

Which one of the following imparts posterior identity in limb development?
A. Apical ectodermal ridge
B. Notocord
C. Primitive streak
D. Progress zone
E. Zone of polarizing activity

A

E. Zone of polarizing activity
In the developing limb, a region of the posterior mesoderm, called the zone of polarizing activity
(ZPA), secretes Shh, which maintains the proximal to distal growth of the limb that is taking place at a distal region
of the limb ectoderm called the apical ectodermal ridge.
In humans, the anterior digit is the thumb, and the posterior digit is the fifth finger. Anterior-posterior patterning is controlled by a region in the posterior
margin of the limb called the zone of polarizing activity (ZPA). The ZPA confers posterior identity of limb mesenchymal cells. Grafting of ZPA to the anterior region of the limb bud results in mirror hand deformity. This
phenomenon suggests the action of a morphogen gradient in specifying digit identity. The critical morphogen in this case is sonic hedgehog (Shh).

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9
Q

Which class of the following signaling molecules is responsible for dorsal patterning in neural tube development?
A. Bone morphogenic protein
B. Cholesterol
C. Fibroblast growth factor
D. Goosecoid
E. Sonic hedgehog

A

A. Bone morphogenic protein

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10
Q

In order to maintain cell proliferation in the developing limb bud, the apical epidermal region secretes into the progress zone
A. FGF8
B. FGF10
C. Lefty
D. Lmx
E. Wnt-7a

A

A. FGF8

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11
Q

Sonic hedgehog plays a role in all of the following developmental processes except
A. determination of differentiation vs self-renewal in stem cells
B. determination of posterior identity of the distal limb
C. left-right axis determination
D. ventral patterning of the neural tube

A

A. determination of differentiation vs self-renewal in stem cells

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12
Q

The Nail-Patella syndrome is caused by defects in the LMX1B gene. This represents a defect in which one of the following?
A. Apoptosis
B. Dorsal patterning of the hand
C. Epidermal-mesenchymal interaction
D. Proximal-distal differentiation
E. Ventral patterning of the hand

A

B. Dorsal patterning of the hand

Mutations in the LMX1B gene cause the nail-patella syndrome, which is characterized by nail dysplasia,
absent or hypoplastic patella, and nephropathy. Since nail and patella are dorsal structures of the limb, this genetic defect can be understood from the developmental genetics standpoint, though much of the details still
require further investigation.

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13
Q

Rapid removal of key intracellular proteins is mediated by
A. Cadherin-mediated cell movement
B. Cilia-mediated direction of fluid flow
C. DNA methylation and histone deacetylation
D. Morphogen-gradient-mediated transcriptional regulation
E. Ubiquitin-mediated processes

A

E. Ubiquitin-mediated processes

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13
Q

Transcription silencing can be mediatd by
A. Cadherin-mediated cell movement
B. Cilia-mediated direction of fluid flow
C. DNA methylation and histone deacetylation
D. Morphogen-gradient-mediated transcriptional regulation
E. Ubiquitin-mediated processes

A

C. DNA methylation and histone deacetylation

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14
Q

Which one of the following signaling molecules is responsible for ventral patterning in neural development?
A. Bone morphogenic proteins
B. Brain-derived neuromorphic factor
C. Fibroblast growth factors
D. Nerve growth factor
E. Sonic hedgehog

A

E. Sonic hedgehog

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15
Q

Which one of the following steps is not necessary for the activation of the sonic hedgehog protein?
A. Attachment of cholesterol
B. Autolytic cleavage
C. Binding to glycosaminoglycan
D. Palmitoylation
E. Removal of signal sequence

A

C. Binding to glycosaminoglycan

16
Q

A newborn infant is found to have dextrocardia (cardiac apex pointing to the right), bilobed right lung and trilobed left lung, polysplenia, and small bowel that loops clockwise. This arrangement of internal organs is best classified as
A. lex situs
B. situs ambiguous
C. situs incognitus
D. situs inversus
E. situs solitus

A

B. situs ambiguous

I guess this is because it doesn’t fit any of those options?

17
Q

Asymmetric distribution of FGF8 during left-right axis determination
A. Cadherin-mediated cell movement
B. Cilia-mediated direction of fluid flow
C. DNA methylation and histone deacetylation
D. Morphogen-gradient-mediated transcriptional regulation
E. Ubiquitin-mediated processes

A

B. Cilia-mediated direction of fluid flow

FGF10 and FGF8 seem to have lots of overlap

18
Q

Which of the following is not considered a midline defect commonly seen in assocaition with holoprosencephaly?
A. Cleft lip and/or palate
B. Hypertrophic pyloric stenosis
C. Hypopituitarism
D. Hypospadias
E. Single upper central incisor

A

B. Hypertrophic pyloric stenosis

can be associated with Shh gene

19
Q

A 6 month old infant is found to have a short neck with poor rotational mobility. There is no other unusual physical finding. This abnormality is likely to represent a
A. AP axis error
B. DV axis error
Heterotaxy
D. Proximal-distal gradient error
E. Segmentation abnormality

A

E. Segmentation abnormality

20
Q

Newborn examination of an infant reveal the PMI of the heart to be on the right chest, and chest X-ray further revealed dextrocardia as well as dextroversion of the heart. However, the chest x-ray also showed the stomach bubble to be onthe left, and the liver appears to be on the right side. On further investigation the left lung is tri-lobed and the right luht lung is bi-lobed, and the spleen is on the left side. This represents
A. Left isomerism
B. Right isomerism
C. situs invertus abdominalis
D. Situs invertus thoracalis
E. Situs inversus totalis

A

D. Situs invertus thoracalis

above the diaphragm it switches

left lung should be 2 lobes
right lung should be 3 lobes

21
Q

Inborn errors of development are enzymatic deficiences that result in congenital malformation(s). All of the following is an example of that EXCEPT
A. 7-Dehydrocholesterol reductase deficiency
B. Galactose-1-phosphate uridyl transferase
C. Phosphomannomutase 2 deficiency
D. Pyruvate dehydrogenase deficiency
E. Tyrosine-protein phosphatase non-receptor type II (PTPN11) deficiency

A

B. Galactose-1-phosphate uridyl transferase

22
Q

Wardenburg syndrome is characterized by craniofacial characteristics, hearing loss, patchy pigmentary allocations of hair and iris and absence of mysenteric ganglions in the colon. Which one of the following is the likely pathogenesis of this syndrome
A. Anterior-posterior segmentation
B/ Left-right determination
C. Melanogenesis
D. Neural crest migration
E. Neural tube formation

A

D. Neural crest migration

23
Q

Deficiency of members of this group mostly results in eye devlopment.
A. FGF receptor genes
B. HOX genes
C. MYC genes
D. PAX genes
E. SHH signaling pathway genes

A

D. PAX genes

24
Q

Defects of this group are often assocaited with midline defects, inclduing those of ventral CNS induction.
A. FGF receptor genes
B. HOX genes
C. MYC genes
D. PAX genes
E. SHH signaling pathway genes

A

E. SHH signaling pathway genes

25
Q

A 30 year old patient is found to have proteinuria. Exam reveals dysplastic nailes and absent patella. A genetic diagnosis is made. Deleterious variant which of the following gene is the most likely?
A. A gene involved in the specification of the anterior-posterior axis of hte limbs.
B. A gene involved in teh specification of the dorsel-ventral ais of the limbs
C. A gene involved in the specification of the proximal-distal axis of the limbs.

A

B. A gene involved in teh specification of the dorsel-ventral ais of the limbs

26
Q

Mechanical alteration of tissue shape involves
A. Cadherin-mediated cell movement
B. Cilia-mediated direction of fluid flow
C. DNA methylation and histone deacetylation
D. Morphogen-gradient-mediated transcriptionalregulation
E. Ubiquitin-mediated processes

A

A. Cadherin-mediated cell movement

27
Q

During embryonic brain development, dorsal-ventral segmentation patterning is strongly influenced by sonic hedgehod signaling. Which one of the following pathways is considered antagonistic to sonic hedgehog signaling?
A. Cadherin signaling
B. FGF signaling
C. Notch signaling
D. TGF signaling
E. Wnt signaling

A

D. TGF signaling

proximal-distal: shoulder-finger and hip-foot
anterior-posterior: thumb-5th finger or
big toe-5th toe, also called cranial-caudal
dorsal-ventral: back-palm of hand or top-bottom of foot

28
Q
  • basal cell carcinoma
  • pitting of palms and plantar areas of feet
  • cysts on mandible
    The most likely genetic diagnosis of this patient concern a cell surface protein involved in which one of the following signaling pathways?
    A. EGF
    B. GFG
    C. SHH
    D. TGF
    E. WNT
A

C. SHH

29
Q
  • no iris
  • cryptorchidism
  • poor growth and motor delay at 6 months
  • left flank mass and hematuria at 9 months
  • tumor left kidney

A. Misense mutation of hte pax 2 gene
B. missense mutation of the pax 3 gene
C. missense mutation of the pax 6 gene
D. chromosome deletion including the pax 2 gene, as well as additional neighboring genes
E. chromosome deletion including the pax 3 gene, as well as additional neighboring genes
F. chromosome deletion including the pax 6 gene, as well as additional neighboring genes

A

F. chromosome deletion including the pax 6 gene, as well as additional neighboring genes

o Pax 2 mutation: coloboma-renal syndrome
o Pax 3 mutation: Waardenburg syndrome
o Pax 6 mutation: aniridia

30
Q

Pax 6 mutation is assocaited with

A

aniridia

31
Q

Pax 2 mutation is associated with

A

coloboma-renal syndrome

32
Q

Pax 3 mutation is associated with

A

Wardenburg syndrome

33
Q

Which one of the following is not a risk factor for holoproscencephaly?
A. heterozygosity for a deleterious variant in the SHH gene
B. Heterozygosity for a deleterious variant in the TBX5 gene
C. History of poorly controlled maternal diabetes during pregnancy
D. Homozygosity of a deleterious variant in the 7-DCHR gene
E. Trisomy 13

A

B. Heterozygosity for a deleterious variant in the TBX5 gene