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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. Initally designed to evaluate the internet as a teaching tool for first year medical students, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than one million visitors each month.

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.

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Pregnancy Timeline by SemestersFetal 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 HemispheresFemale Reproductive SystemEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterSecond TrimesterFirst TrimesterFertilizationDevelopmental Timeline
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News Alerts  May 9, 2013--------News Archive

 
Zebra fish embryos

Functional Studies of rnf216 in Zebrafish.

Panels A through D show dorsal (top) views of control (normal)
zebrafish embryos, and injected embryos. The circles outline the area of the optic tectum,
the structure on which all measurements were based.

The bar graph in Panel E shows the relative size of the optic tectum in control embryos and injected embryos.I bars indicate standard errors. AU denotes arbitrary units.





WHO Child Growth Charts

 

 

 

2 Genes combine to cause rare cerebellar ataxia and reproductive failure

Mutations in genes that regulate cellular metabolism are found in families with a lack of muscle coordination and dementia, as well we reproductive failure.

Researchers from Massachusetts General Hospital (MGH) and Duke University have identified genetic mutations that appear to underlie a rare but devastating syndrome combining reproductive failure with cerebellar ataxia – a lack of muscle coordination – and dementia. In a paper that will appear in the May 23 New England Journal of Medicine and is receiving early online release, the investigators describe finding mutations in one or both of two genes involved in a cellular process called ubiquitination in affected members of five unrelated families.

"This study highlights, for the first time, the importance of the ubiquitin system in a syndrome characterized by ataxia and hypogonadotropic hypogonadism – reproductive failure due to abnormal signaling from the brain or pituitary gland," says Stephanie Seminara, MD, of the Reproductive Endocrine Unit in the MGH Department of Medicine, co-senior author of the report. "It also demonstrates how combining robust genomics with detailed functional assays can unlock complex genetic architecture."


Caused by lesions in the part of the brain responsible for coordination and balance, cerebellar ataxia can begin with difficulty walking or speaking and progress to complete disability of those functions.

Genes associated with several syndromes characterized by ataxia have been identified, but none had previously been associated with the rare combination of ataxia and reproductive failure, which was first described more than 100 years ago.


Several such patients have been referred to the MGH Reproductive Endocrine Unit, including a Palestinian family with several affected members who also developed dementia.

Seminara notes that, while ataxia and hypogonadotropic hypogonadism each may have several possible genetic causes, the combination of both conditions is so rare that it is more likely to be caused by mutations in a particular gene or related genes.

In collaboration with researchers from the Center for Human Disease Modeling at Duke – directed by Nicholas Katsanis, PhD, co-senior author of the NEJM article – her team conducted whole-exome sequencing of DNA from an affected member of the Palestinian family. That screening found rare variants in both copies of 13 genes, and two of those variants were also found in samples from the patient's two affected siblings but not in several unaffected family members.


Both of the mutated genes are involved in ubiquitination, a process by which cellular proteins are marked for degredation by a protein called ubiquitin.

One of the genes, RNF216, codes for an enzyme that attaches ubiquitin to the protein; the other, OTUD4, codes for a protein that removes ubiquitin.

The researchers then sequenced both of these proteins in samples from an additional nine affected individuals from seven different families. They found that one of those individuals had two different RNF216 mutations, four others—two in the same family—had mutations in a single copy of that gene, but none had mutated versions of OTUD4.


All of the individuals with RNF216 mutations had similar medical histories, characterized by a lack of normal hormonal secretion, progressive ataxia and dementia; and all of those with mutations in both genes died in their 30s or 40s. Neuroimaging studies revealed similar brain abnormalities – including atrophy of the cerebellum and cortex – in individuals with RNF216 mutations. The four studied individuals without RNF216 mutations had very different histories, with less severe symptoms.


To get a better idea of the functional consequences of mutations in these two genes, the researchers disrupted their expression in zebrafish and found that blocking either RNF216 or OTUD4 caused disorganization of the cerebellum and reduced the size of eyes and a portion of the midbrain.

The abnormalities were even greater when both genes were blocked—but could be eliminated if production of the relevant proteins was induced by introducing the corresponding human RNA.


"The presence of RNF216 mutations in several familes made its role in causing this syndrome clear, but finding OTUD4 mutation in only one family raised the question of whether it actually contributed to the disease or was just an 'innocent bystander'," says Katsanis. "The zebrafish work provided critical evidence that both genes function in a common pathway, since blocking either of them produced similar effects. And the fact that blocking both genes had a synergistic effect lends further evidence to the two genes' operating in the same pathway and to the contribution of OTUD4 mutations to this syndrome."

Although exactly how these mutations lead to the symptoms seen in these individuals is unknown, the researchers note that identifying these genes may someday lead to therapies—potentially including drugs currently being developed for other disorders involving ubiquitination, including Parkinson's disease—and enable genetic screening and counseling for affected families.

The researchers also want to investigate whether less severe mutations in these genes contribute to the presence of ataxia, dementia or hypogonadism in isolation.

Seminara is an assistant professor of Medicine at Harvard Medical School, and Katsanis is the Jean and George W. Brumley Professor of Cell Biology and Pediatrics at Duke University Medical Center. The co-lead authors of the NEJM report are David Margonin, MD, PhD, MGH Department of Neurology; Maria Kousi, PhD, Duke Center for Human Disease Modeling; and Yee-Ming Chan, MD, PhD, MGH Reproductive Endocrine Unit and Boston Children's Hospital. The study was supported by National Institute for Child Health and Human Development grants R01 HD043341, R01 HD042601 and U54 HD028138 and by other National Institutes of Health grants.

Duke Medicine encompasses the Duke University Health System, the Duke University School of Medicine, and the Duke University School of Nursing. Its mission is to serve as a world-class academic and health care system, working to transform medicine and health locally and globally through innovative scientific research, rapid translation of breakthrough discoveries, education of future clinical and scientific leaders and the highest quality of medical practice in the community and beyond.

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of more than $775 million and major research centers in AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, reproductive biology, systems biology, transplantation biology and photomedicine. In July 2012, MGH moved into the number one spot on the 2012-13 U.S. News & World Report list of "America's Best Hospitals."

Original article: http://www.massgeneral.org/about/pressrelease.aspx?id=1586