1a Disorders of Early Development Flashcards

1
Q

What can cause pregnancy loss in humans?

A
  • Errors in embryo-fetal development
  • Failure of the embryo to implant in the uterine lining
  • Inability to sustain development of the implanted embryo
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2
Q

What is meant by a miscarriage?

A

Loss of pregnancy before 23 weeks gestation

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3
Q

What is the definition of a early clinical pregnancy loss?

A

Loss before 12 weeks gestation

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4
Q

What is meant by a late clinical pregnancy loss?

A

Loss of pregnancy after 24 weeks gestation

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5
Q

What is meant by recurrent misscarriage?

A

In the UK, defined as three or more pregnancy losses

US: two or more pregnancy losses

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6
Q

What is the major cause of early pregnancy loss?

A

Aneuploidy (chromosome number errors)

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7
Q

How does the risk of trisomic pregnancy increase with materal age?

A

Exponential increase

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8
Q

Why does aneuploidy increase with maternal age?

A

As the mother gets older, the cohesion proteins which hold the chromatids of homologous chromosomes together are degraded, leading to a loss of cohesion between the chromatids - results in the chromatids separating and drifting during mitotic division rather than being segregated accurately

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9
Q

What is the name of two cohesion proteins involved in maintaining cohesion between chromatids within chromosomes?

A

REC8 and SMC2

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10
Q

What proportion of conceptions are lost before the pregnancy is detectable by ultrasound scan?

A

50%

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11
Q

What do embryos require to be viable?

A

Meternally and paternally derived genomes

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12
Q

What happens when the spindle cannot grad a hold of the chromatids peoperly?

A

Leads to non-disjunction leading to aneuploidy

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13
Q

What causes a complete molar pregnancy?

A

When an empty egg is fertilised by one or two sperm, resulting in all the genetic material from the father

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14
Q

What is meant by a partial /incomplete molar pregnancy?

A

When a normal egg is fertilised by two sperm, so the embryo has three sets of chromosomes

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15
Q

Which genome drives placental development?

A

Paternal genome

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16
Q

Which genes are only expressed from the paternally inherited copy?

A

genes which promote the embryos fitness to survive at the expense of the mother

17
Q

Which genes are only expressed from the maternally inherited copy?

A

Genes which restrict embryo fitness to conserve resources for future pregnancies

18
Q

What happens genetically when there is a molar pregnancy?

A

There is a genetic imbalance - eg if more paternal genes are expressed, there will be less of a balance and placenta will be enlarged

19
Q

Why do complete molar pregnancies result in enlarged placentas?

A

There is a genomic imbalance, meaning more paternally-inherited genes are expressed, leading to a lot of placental development

20
Q

What are gestational trophoblastic diseases?

A

A collection of disorders characterized by overgrowth of trophoblastic tissue

21
Q

What is the difference between a complete and partial hydatidiform mole?

A

in a complete hydatidiform mole, there is no fetal tissue, but there is fetal tissue in a partial one

22
Q

What is an example of a benign gestational trophoblastic disease?

A

Hydatidiform mole

23
Q

What forms when the gestational trophoblastic disease becomes malignant?

A

Forms a gestational trophoblastic neoplasia

24
Q

What are rare examples of malignant gestational trophoblastic neoplasias?

A

Invasive moles, Choriocarcinoma

25
Q

What are very rare examples of malignant gestational trophoblastic neoplasias?

A

Placental site trophoblastic tumour, epithelioid trophoblastic tumour

26
Q

What is meant by an ectopic pregnancy?

A

When the embryo implants at a site other than the uterine endometrium

27
Q

Where do the majority of ectopic pregnancies occur?

A

In the fallopian tubes

28
Q

What can occur if the ectopic pregnancy ruptures?

A

Severe internal bleeding

29
Q

What chemical in cigarette smoke regulates the expression of PROKR1?

A

Cotinine

30
Q

What does PROKR1 do?

A

regulates fallopian tube smooth muscle contractility

31
Q

What does cotinine induce in fallopian tube explants?

A

Pop-apoptosis protein expression

32
Q

Why does smoking reduce tubal transit of the embryo?

A

tobacco smoke inhibits cilia function

33
Q

What factors increase the risk for ectopic pregnancy?

A

Prior ectopic pregnancy or fallopian tube surgery, STIs, pelvic inflammatory disease, endometriosis

34
Q

What is endometriosis

A

When parts of the endometrium start growing in other places like the

35
Q

What may underpin recurrent miscarriage/pregnancy loss?

A

Disruptions of local signalling pathways controlling implantation

36
Q

What is endometriosis

A

When parts of the endometrium start growing in other places like the