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The zygote chromosome in the case of a complete hydatiform mole is product of;
1- empty ovum fertilization by 2 sperms OR
2- empty ovum fertilized by 1 sperm which its DNA is duplicated later on?

Thanks
 

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The two mechanisms possible

Complete Moles:
Your number 2 option is seen in approximately 80% of moles, the most probable mechanism is that an empty egg is fertilized by a single sperm, followed by a duplication of all chromosomes/genes (a process called "endoreduplication").

Your number 1 option is seen in approximately 20% of complete moles the most probable mechanism is that an empty egg is fertilised by two sperms.

In both cases, the moles are diploid (i.e. there are two copies of every chromosome). In all these cases, the mitochondrial genes are inherited from the mother, as usual.

Partial Moles:
Most partial moles are triploid (three chromosome sets). The nucleus contains one maternal set of genes and two paternal sets. The mechanism is usually the reduplication of the paternal haploid set from a single sperm, but may also be the consequence of dispermic (two sperm) fertilization of the egg.

Reference: Pathology of the placenta By Harold Fox, Neil James Sebire, Page 432
 

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The zygote chromosome in the case of a complete hydatiform mole is product of;
1- empty ovum fertilization by 2 sperms OR
2- empty ovum fertilized by 1 sperm which its DNA is duplicated later on?

Thanks
Complete Moles:
  • 80% are 1 sperm which is duplicated (homozygote, uniparental, unispermy, always 46XX)
  • 20% are 2 sperms (heterozygote, uniparental, dispermy, could be 46XX or 46XY)

:)
 

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Discussion Starter #4
@mondoshawan;
what is your refrence for this "20% are 2 sperms (heterozygote, uniparental, dispermy, could be 46XX or 46XY" cause i had this thought that complete mole is only 46xx.
thanks
 

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@mondoshawan;
what is your refrence for this "20% are 2 sperms (heterozygote, uniparental, dispermy, could be 46XX or 46XY" cause i had this thought that complete mole is only 46xx.
thanks
Hydatidiform Mole: eMedicine Obstetrics and Gynecology

They also say that 90% are XX and 10% are XY - which makes sense, if all 80% that are homozygous are XX and half of the 20% that are heterozygous are XX.

DynaMed also cites the 90%/10% for XX/XY

hope that helps!
 
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