Welcome to The Visible Embryo

Home- - -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs in Pregnancy- -- Pregnancy Calculator- --Female Reproductive System- News Alerts -Contact


Welcome to The Visible Embryo, a comprehensive educational resource on human development from conception to birth.

The Visible Embryo provides visual references for changes in fetal development throughout pregnancy and can be navigated via fetal development or maternal changes.

The National Institutes of Child Health and Human Development awarded Phase I and Phase II Small Business Innovative Research Grants to develop The Visible Embryo in 1993 as a first generation internet teaching tool consolidating human embryology teaching for first year medical students.

Today, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than 1 million visitors each month. The field of early embryology has grown to include the identification of the stem cell as not only critical to organogenesis in the embryo, but equally critical to organ function and repair in the adult human.

The identification and understanding of genetic malfunction, inflammatory responses, and the progression in chronic disease, begins with a grounding in primary cellular and systemic functions manifested in the study of the early embryo.


WHO International Clinical Trials Registry Platform
The World Health Organization (WHO) has created a new Web site to help researchers, doctors and patients obtain reliable information on high-quality clinical trials. Now you can go to one website and search all registers to identify clinical trial research underway around the world!



Home

History

Bibliography

Pregnancy Timeline

Prescription Drug Effects on Pregnancy

Pregnancy Calculator

Female Reproductive System

Contact The Visible Embryo

News Archive
Disclaimer: The Visible Embryo web site is provided for your general information only. The information contained on this site should not be treated as a substitute for medical, legal or other professional advice. Neither is The Visible Embryo responsible or liable for the contents of any websites of third parties which are listed on this site.
Content protected under a Creative Commons License.

No dirivative works may be made or used for commercial purposes.

Return To Top Of Page
Pregnancy Timeline by SemestersFemale Reproductive SystemFertilizationThe Appearance of SomitesFirst TrimesterSecond TrimesterThird TrimesterFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterDevelopmental Timeline
Click weeks 0 - 40 and follow fetal growth
Search artcles published since 2007

December 17, 2012--------News Archive Return to: News Alerts


Researchers have found a possible heredity mechanism that predisposes children to
acute lymphoblastic leukemia (ALL), the most common type of blood cancer in children.






WHO Child Growth Charts

       

Genetic Defect in Sex Cells May Predispose to Childhood Leukemia

A rare, atypical form of the PRDM9 fertility gene was found in parents of leukemic children

Researchers at the Sainte-Justine University Hospital Center and the University of Montreal have found a possible heredity mechanism that predisposes children to acute lymphoblastic leukemia (ALL), the most common type of blood cancer in children.

According to their findings published in Genome Research, the presence of a genetic defect in the egg or sperm from which children having ALL arise may be a prerequisite for the disease to develop. A significant number of children with ALL are thought to inherit a rare PRDM9 gene variant responsible for the abnormal sex cells–a gene variant that puts their own children at risk of having ALL-predisposed offspring.

"Our findings indicate ALL susceptibility to be partially hereditary. However, it is not classic heredity in the sense that the abnormal genetic variant does not need to be passed from parent to child for offspring to have the disease," explains Julie Hussin, a doctoral student in Genomics under the direction of Dr. Philip Awadalla, a genetics researcher.

"Instead, the genetic defect in the egg or sperm from which the children developed is thought to predispose them to leukemia," continues Julie Hussin. "However, only the children who inherit the genetic variant run the risk of transmitting ALL predispositions to their offspring."

According to the study, more than three fourth of families with affected children have an atypical form of the PRDM9 gene, but only half the patients inherited this genetic variant. The defect is expressed by chromosome recombinations at unusual points during gamete formation (eggs in girls, sperm in boys).


While an abnormal gamete may lead to ALL
development, this condition alone is not enough.

"Triggering the process of cancer cell proliferation
inevitably requires a second hit, such as other
mutations or environmental factors."

Julie Hussin.
doctoral student, Genomics


Until now, few pediatric cancer studies have analyzed data from parents, as scientists generally focus on studying children, their tumors or their environment, especially during pregnancy. "Parents have to be included in these studies. Our findings demonstrate the importance of including parents' genetic information for the understanding of childhood leukemia, as well as other early childhood diseases," added Dr. Philip Awadalla, the lead principal investigator on the study.

The findings were replicated in a cohort of American children with ALL through a collaboration of the Sainte-Justine University Hospital Center in Montreal, Canada, and St. Jude Children's Research Hospital in Memphis, USA.


Acute Lymphoblastic Leukemia Model of Heredity

At least one parent with/without leukemia produces abnormal gametes and carries a rare PRDM9 allele

Two Children
Both have leukemia, since each develops from an abnormal gamete

Child 1
Receives the rare allele in its genome
Produces abnormal gametes
Risks having children with leukemia

Child 2
Does not receive the rare allele
Produces normal gametes
Does not risk having children with leukemia

About the researchers
Julie Hussin, doctorate student in bioinformatics

* Sainte-Justine University Hospital Center, department of hematology/oncology
* Department of biochemistry, Université de Montréal

Dr Philip Awadalla

* Principal investigator, Sainte-Justine University Hospital Center
* Professor, department of pediatrics, Université of Montréal
* Principal investigator and scientific director, CARTaGENE

Scientific paper

* « Rare allelic forms of PRDM9 associated with childhood leukemogenesis » in Genome Research, December 5, 2012.

Original article: http://www.eurekalert.org/pub_releases/2012-12/uom-agd121712.php