Scientists Map Entire DNA of Human Fetus

December 10, 2010

Courtesy: foxnews.com

Parents may soon be able to find out if their unborn child is prone to any inherited diseases, researchers said on Thursday, after developing a non-invasive technique to draw the entire gene map of the human fetus.

By analyzing a sample of the mother’s blood, which contains DNA from the fetus, scientists in Hong Kong and the United States were able to identify all the DNA strands that belong to the child and piece them together.

“Before this work, people only could look for one disease at one time but now you can construct a screen for a number of diseases which are prevalent in any particular population,” said lead author Dennis Lo, professor of medicine from the Chinese University in Hong Kong.

The research team’s breakthrough was discovering that the mother’s plasma holds the entire fetal genome. Previously, only part of the baby’s DNA was thought to be in the mother’s blood.

“Now that we know (the) entire fetal genome is in there, you can look for any disease that is genetically inherited.”

The study, published in the journal Science Translational Medicine on Thursday, recruited a couple undergoing prenatal diagnosis for a hereditary blood disorder, beta-thalassemia.
“In the mother’s blood, 90 percent of the DNA is her own … and 10 percent is the baby’s. Half of the fetal genome is from father and half from mother,” Lo said.

Lo described the process as akin to putting together a jigsaw puzzle with millions of pieces — only in this case, 10 times as many pieces from a much larger jigsaw were mixed in with it too.

“The whole genome is fragmented into millions of pieces and by this exercise, we assemble it back,” Lo said.
“It’s like assembling a jigsaw puzzle with millions of pieces. But to make it more challenging, you mix in 10 times (the number of pieces) from another jigsaw puzzle, that’s the mother’s own DNA. And you are trying to assemble the child’s.”

Experts who were not involved in the study called for caution.

“It is too early to apply the technology widely as we are not yet able to interpret many of the results that can be generated accurately,” said Christine Patch, chair of the British Society for Human Genetics. “We do not randomly test pregnancies for a long list of … conditions that may only manifest in adult life on the basis that individuals may not want to know that information when they are older.”


Chinese Study Suggests New Way to Test for Genetic Diseases

December 10, 2010

Courtesy: health.usnews.com

A new test that requires only a tiny sample of a mother’s blood to scan the genome of a fetus may offer a safer alternative to current methods of prenatal screening for genetic diseases, a new study suggests.

Currently, a sample of fetal tissue is collected using invasive procedures such as amniocentesis or chorionic villus sampling, both of which pose a small but definite risk to the fetus.

But, Chinese researchers found that fetal DNA floating in the mother’s blood contains the entire fetal genome and can reveal a number of genetic and chromosomal disorders in the fetus.

They used the method on a couple undergoing prenatal diagnosis for a type of genetic anemia called beta-thalassemia. The results showed that the fetus had inherited the beta-thalassemia mutation from the father and a normal gene from the mother, meaning the fetus was a carrier of the disease.

The study is published in the Dec. 8 issue of Science Translational Medicine.


Genetic infertility treated successfully at Mumbai hospital

November 24, 2010

Courtesy: dnaindia.com

A woman with a rare genetic disorder ‘Robertsonian Translocation’, resulting in infertility, has delivered a healthy baby girl at the Jaslok Hospital and Research Center.

“With this first Invitro fertilisation (IVF) using pre-implantation genetic diagnosis (PGD), India joins a handful of countries that have accomplished successful management of this disorder,” Dr Firuza Parikh, Director, Assisted Reproduction and Genetics at Jaslok and former Professor at the Yale University School of Medicine, USA, said.

The baby girl was delivered yesterday at city’s Jaslok hospital, Parikh said adding that this case report was published as a cover article in the peer reviewed ‘Journal of Prenatal Diagnosis and Therapy’ (January- June 2010).

Attributing the success to her team of 40 individuals particularly Dr Prochi Madon, Dr Arundhati Athalye, Mr Nandkishor Naik and Dattatray Naik, Parikh explained, “We are born with 46 chromosomes which occur in pairs. Each chromosome of a pair is a mirror image of the other. Although this harmony ismaintained in nature, an occasional slip results in a translocation.”

“As the name suggests, a segment or an arm of one chromosome transports itself onto another chromosome and one such rearrangement is called a RobertsonianTranslocation after the American geneticist Dr W Robertson,” she said.

“The rearrangement can occur in males and females who do not manifest any clinical symptoms. The problem manifests when the couple tries to conceive,” Parikh said.

“An embryo derives half its chromosomes from the father and half from the mother. Hence if the chromosome with extra genetic material goes into the embryo, the amount of genetic material of that chromosome triples resulting in miscarriage or mental retardation,” the In-vitro fertilization (IVF) expert said.

The embryos were screened using Pre-implantation Genetic Diagnosis (PGD).

Eleven years ago, Parikh and Madon established PGD for genetic disorders for the first time in India at the Jaslok Hospital and Research Centre.

Parikh who led this procedure, said, “PGD requires years of perfection, team work and a thorough knowledge of reproductive biology and genetics. The couple first undergoes IMSI (intracytoplasmic morphologically selected sperm injection).

In this procedure the egg and the sperm are magnified 7000 times. With the help of a sharp pipette a single sperm is injected into the egg and the resulting embryo is ready for PGD when it reaches the eight cell stage.”

“A laser beam swiftly cuts open the shell of the embryo, a fine glass pipette is advanced towards one of the cells of the embryo. Using gentle suction, a single cell is aspirated. This cell is then processed by the genetics team,” Parikh said.

Madon, chief geneticist added, “The cell is put through an overnight procedure called Fluorescence In Situ Hybridisation (FISH), a procedure to zip open the DNA strands and attach coloured probes, to identify the chromosomes of interest.”

In this particular couple, the wife had a translocation between chromosomes 13 and 14. Two embryos underwent the procedure of PGD. This embryo was transferred into the mother’s womb, resulting in the birth of a healthy baby girl.

“PGD is an effective form of treatment for couples at a risk for Down Syndrome and other chromosomal abnormalities, for women approaching 40, those with repeated failed attempts at IVF/ICSI (Intracytoplasmic sperm injection), those women showing poor quality embryos and for severe male factor infertility. It is also helpful in some rare genetic diseases like haemophilia,” Parikh said.

“We are now in the process of setting up a facility for PGD to detect embryos at a risk of Thalassemia. We have also started offering this procedure routinely to couples undergoing IVF/ICSI in order to select normal embryos so that less number of embryos are transferred,” she said.

This will increase the chances of a normal pregnancy and decrease the chances of a miscarriage. This technique is called pre-implantation genetic screening (PGS), Parikh added.


Studying Tropical Genetic Blood Diseases

October 16, 2010

Sir David Weatherall, 77, an Oxford researcher-physician, was among the first to use the tools of molecular biology to understand thalassemia. He was in New York to receive the Lasker-Koshland Special Achievement Award for “50 years of international statesmanship in biomedical science.” A condensed version of  conversations with him follows:

Q. YOU GREW UP IN LIVERPOOL. HOW DID TROPICAL GENETIC BLOOD DISEASES BECOME YOUR LIFE’S WORK?

A. In 1956, after I’d finished my medical training, I was drafted for compulsory military service. At the time, there was an insurgency in Malaya, where the Commonwealth forces were fighting the Communists, and I was not anxious to get involved with that. Nonetheless, I soon found myself on a troop ship for Singapore.

When I got there, because I had no pediatric training, the army put me in charge of a children’s ward looking after the families of Commonwealth soldiers. And there I encountered a 2-year-old, the daughter of a Gurkha from Nepal. She had profound anemia. No one understood why. We kept her alive with transfusions.

So in my spare moments, I went to the biochemistry department at Singapore University Hospital, and worked with people there to try to figure it out. Within six months, we had an answer: thalassemia. That was a big surprise. This genetic disease was thought to occur only in the Mediterranean.

Q. WHAT EXACTLY IS IT?

A. It’s a defect in the genes that makes it impossible for hemoglobin to properly form. Of course, in the 1950s, we understood little about hemoglobin’s biochemistry. Thalassemia was, and is, a terrible disease. The children generally don’t live to adulthood — and then only with constant transfusions. In the case of this little girl, her parents eventually took her to their village in Nepal, where she died.

Q. SO SHE WAS THE BEGINNING OF YOUR INTEREST?

A. Yes. The army next sent me up to northern Malaya, where the last of the fighting was going on. I used this time to search for more thalassemia. I’d construct equipment from old car batteries and filter paper, and that’s how I separated the different hemoglobins in the blood samples I’d collect. Whenever I found anything abnormal, I’d post the slides to a good old boy, Herman Lehman, at a laboratory in London. We actually found one or two more cases that way.

Read Complete Interview Here..


Genetics project launched to cut infant deaths

October 12, 2010

Courtesy: bionews.org.uk

A three-year genetics project has been launched in Birmingham to help tackle the city’s high infant mortality rate by raising awareness of inherited genetic disorders. The project has three strands: educational, clinical and primary care.

The primary care strand of the project, which was launched this week, aims to raise the profile of inherited genetic disorders through the public’s engagement with GPs. Three GP practices in the Heart of Birmingham Teaching Primary Care Trust are offering a screening programme for inherited blood disorders, such as sickle cell anaemia and thalassemia. They are raising awareness of other genetic disorders and are identifying families appropriate for specialist referral. The clinical strand of the project includes developing 30 new molecular tests for genetic diseases over the next three years. ‘We wanted to launch in primary care to raise the profile of this area among GPs and Primary Care’, said project manager Yasar Eltaf, from the Birmingham Women’s hospital.

The project’s focus is on genetic risk generally, but first-cousin marriage is a risk factor for inherited genetic disorders. Birmingham’s infant death rates were linked to first-cousin marriage by a Channel 4 Dispatches programme aired in August this year. A community educator from the Enhanced Genetic Services Project, Zahira Maqsood, emphasised: ‘This project is not about chastising families and community groups for their marriage and cultural choices. It is about enabling people to be aware of potential health risks and choices available to them’.

Infant death rates in Birmingham are 8.2 per 1000 population, almost double the national average of 4.8 per 1000 population. About 139 infants die each year in the city.

 


Apollo Hospitals introduces coagulation screening test

September 7, 2010

Courtesy: thefinancialexpress-bd.com

Apollo Hospitals, Dhaka has introduced a coagulation screening test in single blood sample in its lab medicine department, according to a press release.

Coagulation screening test provides precise diagnosis of any abnormality of blood coagulation as in hemophilia, thalassemia, blood malignancy, other malignancy or any genetic disorder.

This screening consists of a set of seven tests like Bleeding Time (BT), Clotting Time (CT), Platelet count, Prothrombin Time (PT), Activated Partial Thromboplastin Time (APTT), Thrombin Time (TT) and Fibrinogen assay in a single blood sample collection.

The report will be delivered same day after 5:00 pm if sample is received within 12:00 noon, if later then it will be delivered next day after 10:00 am, the release added.


UAE Genetic Diseases Association carries on initiative for UAE free from thalassemia by 2012

July 30, 2010

Courtesy: ameinfo.com

UAE Genetic Diseases Association (UAEGDA), the sole non-profit genetic organization in the UAE, recently announced that they are on track to achieve their “UAE Free from Thalassemia 2012” initiative, saying that the target looks quite achievable to eliminate births of children born with the genetic blood disease within the next two years.

Offering free and confidential testing and in association with National Bonds Corporation PJSC, the organisation held a blood screening drive earlier this week for its employees to screen them for the most commonly inherited blood genetic disorders—including as Beta Thalassemia, sickle cell anaemia, G6PD deficiency and Diabetes Mellitus—in support of UAEGDA’s national health campaign.

Regularly organized screening drives help to increase an individual’s awareness on the health risks posed by genetic blood disorders, which can be passed from one generation to the other. The process begins by registering online at the UAEGDA website. Bar-coded labels are then printed and placed on the individuals testing tubes after which the sample of blood is processed in the UAEGDA laboratory. The results are then sent directly to the individual’s email with all the details being handled solely between the client and the organization.

Dr. Maryam Matar, Founder & Chairman of UAEGDA, says that genetic blood diseases like thalassemia are highly prevalent in the UAE but can be addressed with a simple and inexpensive blood test as a primary solution in helping to reduce the presence of hereditary diseases in the country.

“We are confident that with the rapid increase in the activities of our organization and with all the awareness events organized by UAEGDA across the country, we can make the UAE free of thalassemia by 2012,” adds Dr. Matar.

As one of UAEGDA’s leading partners, National Bonds Corporation PJSC takes responsibility towards its employees seriously and is working in association with UAEGDA to support the government’s campaign to eradicate thalassemia in the country by 2012.

“We are committed to stepping up the fight against thalassemia and working towards the health of the nation, both in terms of physical and financial wellbeing,” comments Mr. Mohammed Qasim Al Ali, CEO of National Bonds Corporation PJSC.

“By offering our employees UAEGDA’s free and confidential voluntary tests, we can ensure their own wellbeing as well as that of future generations.”

The UAE Genetic Diseases Association has been able to considerably reduce the impact of common genetic disorders prevalent in the country through its community outreach programs, health education, counseling and free screening tests. They also have a free genetic clinic equipped with a state-of-the-art screening facility supervised by internationally renowned experts.


%d bloggers like this: