World-famous Down syndrome researcher
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Irene Uchida has been asked to join the morning hospital rounds at Children’s Hospital in Winnipeg, Manitoba. It’s around 1960. She’s talking about patients who have the symptoms of trisomy of chromosome 18 — that is, three number 18 chromosomes instead of the normal two. A doctor named Jack Sinclair raises his hand and says, “Hey, I think we have one on the fourth floor.”
He takes her up to the ward right away. They get a blood sample from the patient and add some anti-clotting agent. Uchida immediately goes to work to identify the chromosomes. Diagnosing trisomy by actually looking at a patient’s chromosomes is something very new, and it has never been done by anybody in Winnipeg — or even in Canada.
She takes the blood to the cytology lab, a place in the hospital for examining cells. The lab has the vinegary smell of acetic acid. Low tables by the windows have lots of microscopes, with technicians in white lab coats seated at most of them. Along the opposite wall, a few people are preparing samples and slides.
First Uchida lets the red blood cells settle in the vial, then she takes the white blood cells off the top with a pipette, a long glass tube that is used to suck up small amounts of liquid. She transfers them to a small glass container containing a medium in which they grow and multiply for three days, inside an incubator. Then she takes out the liquid and centrifuges it down. A centrifuge is a device that spins test tubes around super-fast to force all the heavy stuff to the bottom, leaving lighter cells and liquid at the top. She “fixes” the cells with acetic acid solution, and drops them onto a glass slide so that the cells break and spill out their chromosomes. She stains the material on the slide with a dye, puts it under the microscope and looks for the chromosomes — long, twisty, banded strands of protein and DNA. She finally does find three number 18 chromosomes instead of the normal two, confirming the diagnosis. This cytogenetic analysis is a first for Winnipeg and Canada.
Image by: Freelance Illustration and Graphics.
At the University of British Columbia (UBC) Irene Uchida was a member of the Japanese Students Club and a reporter for a weekly Japanese-Canadian newspaper. During World War II she was active in the group Japanese Canadian Citizens for Democracy. Because Canada was at war with Japan and feared an invasion, it was a period of great anxiety for the 23,000 people of Japanese heritage who were uprooted from their homes on the West Coast by an order-in-council of the federal government in 1942 and had their possessions and properties seized.
Uchida was forced to stop her education at ubc and leave her home in Vancouver. She and her family were taken to an internment camp at Christina Lake in British Columbia’s Kootenay region, where she became principal of the largest internment-camp school, at nearby Lemon Creek. She became known for her creative ideas. Two years later she was allowed to continue her education at the University of Toronto, graduating in 1946 with a bachelor of arts. She planned to take up social work, but one of her professors persuaded her to enter the field of genetics.
In 1951 Uchida received her doctorate in zoology and began her career as a research associate at the Hospital for Sick Children in Toronto. Her work in genetics focused on the study of twins, children with congenital heart diseases and those with a variety of other anomalies such as Down syndrome.
In 1959, while working with Drosophila (fruit fly) chromosomes at the University of Wisconsin, Uchida turned her attention to human chromosomes. When scientists in France discovered that Down syndrome patients had an extra chromosome (47 instead of 46), she decided to try to learn the cause of the extra chromosome. She continued her research in Winnipeg when she was appointed director of the Department of Medical Genetics at Children’s Hospital there, in 1960. In her first study of human chromosomes, Uchida found that there appeared to be an association between pregnant women who received X-rays and the occurrence of Down syndrome in their babies.
In 1969, with a Medical Research Council grant, she went as a visiting scientist to the University of London and to Harwell, England, to study a technique for analyzing the chromosomes of mouse eggs.
After returning to Canada, Uchida continued her research on the effects of radiation on humans and mice at the McMaster University Medical Centre in Hamilton, Ontario, as well as carrying out her teaching duties as a professor. She also initiated a Genetic Counselling Program at the McMaster Medical Centre. As director of the Cytogenetics Laboratory in Oshawa, Ontario, her responsibilities included the diagnosis of chromosome differences in patients with congenital abnormalities, developmental disabilities and other genetic conditions. In addition, Uchida helped diagnose irregularities in the chromosomes of fetuses. She has been invited to speak in many countries and is a member of various provincial, national and international scientific organizations.
Cytogenetics is the study of chromosomes in cells. It concentrates on the behaviour and identification of chromosomes. By knowing the state of the chromosomes and especially the genes within them, scientists can now predict many genetic disorders. Uchida was the first person to bring this technique to Canada. One of the many practical applications of cytogenetics is the ability to diagnose genetic diseases in fetuses, thus preparing many pregnant mothers and their spouses for the birth of an abnormal child, or giving them the choice of terminating the pregnancy.
1. In humans, 23 pairs of chromosomes have tens of thousands of genes that carry the information needed to create a unique person. For each pair, one comes from the father, the other from the mother. The bands indicate different types of DNA (DeoxyriboNucleic Acid—the molecule that contains genetic information). Cytogeneticists use the bands to help match the pairs.
2. These are the chromosomes of Jodi Kaczur, a Special Olympics champion and actor, who happens to have Down syndrome. You can tell by Jodi’s two X chromosomes that she is a girl. Boys have one X and one Y chromosome.
3. Down syndrome is caused by the accidental tripling of chromosome number 21 during conception. It was first described by the English physician John Langdon Down in 1866. Other genetic diseases are caused by tripling of chromosomes number 13 or 18. The tripling is called trisomy. People with trisomy of chromosomes 13 or 18 usually die as fetuses, and are miscarried. Those who are born alive do not usually live more than a year. The incidence of Down syndrome is related to the age of the pregnant woman. Women under 30 have a 1 in 1,200 chance of having a Down syndrome baby. By age 35 the chance is about 1 in 500 and by age 45 about 1 in 25.
4. Jodi with actor Arnold Schwarzenegger. People with Down syndrome are not as different as you might think. According to Uchida, who has known hundreds of them, “They are often very happy and affectionate.” Yet like everyone else, they have unique personalities with strengths, weaknesses, interests, dreams and ideas. New education and training programs are helping Down syndrome people live happy productive lives. Unfortunately, because of health problems arising from their genetic disorder, only a few live beyond their mid fifties.
Uchida believes geneticists may be able to find out how to deactivate one of the chromosomes in an individual with trisomy. This happens naturally during the embryonic development of all women — one of their X chromosomes is always deactivated. If geneticists can find a technique to deactivate certain chromosomes such as the extra ones at numbers 21, 13 or 18, the related genetic conditions may be cured at an early embryonic stage.
Jason Kingsley and Mitchell Levitz, Count Us In: Growing Up with Down Syndrome, Harvest/HBJ Books, 1994.
Library and Archives Canada has a webpage about Uchida.
The Canadian Down Syndrome Society is a good source for more information.
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