M1NHAZ All became genuinely concerned after his wife got pregnant for the third time. Since they had their first child in 1990, who died in a year afflicted with thalassemia. All had been playing a game of Russian Roulette, but this time medical , advances gave some genetic odds in his favour. All took his wife to a genetic testing hospital in a neighbouring country. And the hospital genetic testing I report relieved him of the I tension and fear he had been I harbouring since he leant about ; his wife's third pregnancy.

All now has learnt that J somewhere on a stretch of his ancestor s DN/\ - the blueprint r of the human body -- a genetic j command unit called betaglobin gene went awry. The re-i suit was that children In All's j family had died of thalassemia, । a blood disorder that means a i lifetime of blood transfusions --I and a life not more than 20 , years. Most shocking, his first child born In 1990 was diagnosed as thalassemlc within a year. His second child Kamila has to have blood transfusion every three months. Pressure from his parents was mounting to have a normal baby. So when his wife got pregnant in 1995. All shaken with fear and anxiety went to a genetic testing hospital in India to have the DNA of his unborn child tested. Shockingly enough, he and his wife were both carriers of the faulty gene. But now he has learnt that his unborn child has not Inherited it. In 1996. Fatema was born and this time God answered to his prayers. Fatema. who had a one-in-four chance of being a thalassemlc. was born normal.

Fortunately for All. he is the recipient of the gift of genetic testing, the scientific ability to read the body's blueprints to foresee what they will build or tear apart. He might have been a fortunate one among thousands in the country to have discovered the trauma of fixing with diseases ordained by defects in their genes. Adx’ances in medical science In recent times have revealed that genetic hand plays the part in many such diseases like Haemophilia. Alzheimer. Marfan Syndrome. Dyslexia. Fragile X-syndrome. Cystic Fibrosis and night blindness.

Some very outstanding personalities and members of the royal families were victims of genetic diseases Emperor •. George III (1738-1800) was a victim perfiria disease. Queen Victoria (1819-1901) was a carrier of Haemophilia. Alexy. the only son of the last Czar of Russia. xvas a carrier of Haemophilia A. President Abraham Lincoln was a victim of Marfan Syndrome and President Ronald Reagan is now learnt to be suffering from Alzheimers.

Most of the diseases, unless the patients come of an affluent family, are crippling and devastating to their families. But. sure enough in recent times, pre-natal DNA tests, explorations of the human genome (the complete genetic text of

human) and the complete screening of communities vulnerable to particular genetic defects hold the promise of a new predictive medicine that could afford the opportunity to avoid, prevent or even treat genetic disorders. It is neither unusual nor rare that a child is born of healthy parents with serious ailments, mostly a result of genetic fault. May be. the defective gene lurking tn their parents or even ancestors may suddenly appear at the time of birth. As such the power to look into your future Is important because there could be millions in the country with rogue genes. And in a country swept by mass diseases like malaria, tuberculosis. diarrhoea and influenza, caused by all manners of druses and bacteria, no one really had the time, money, ex-

pertise or even diagnostic tools to look for flawed genes in the helical wilderness of DNA. Now some hospitals and specialised centres for genetic testing have set up units that cater to a growing list of disorders.

Even in India the government is funding genetic studies of Indian communities. Many centres in the private sector have come up throughout the length and breadth of India that offer counselling to families with gene disorders and do tests for the new diseases appearing in the country’ side.

Take the case of Brianna of Washington who came to hospital for treatment. Brianna had never drawn an easy breath. When she was a baby her tiny chest convulsed at the slightest irritation. Instead of laughing, she would cough. Instead of crying. gag. She suffered from an endless string of infections --pneumonia, a cold bronchitis --that ordinary* antibiotics seemed powerless to curb. Brianna weighed less at one year than she did at six months. Finally. at an age just after the child's third birthday, her anxious parents took her to the University of Washington Pulmonary clinic at Seattle. Chest X-ray revealed that thick bluish mucus had started to accumulate in her airways. "She already had some permanent scarring to the lungs." said Dr. Bonnie Ramsey. Brian's physician and an expert in lung dis-

Brianna was suffering from cystic fibrosis, the most common inherited disorder among whites and a disease that afflicts about 25000 -Americans.

killing more than 500 a year. Doctors now say that Just 10 years ago. the prospects of a girl her age were as bleak as they were Inevitable. Doctors in the US further assert that as the combination of chronic infections. clogged airways and digestive problems took their toll, she could not have expected to outlive her teens. But now. says Ramsey, "Brianna has an excellent chance of living Into adulthood.' In fact. Ramsey says, as things stand today. Brianna and thousands of other babies born with CF in the past few years may even live to see a cure. So says Ramsey. "In the next decade, we are going to see a revolution In treatment for this disease."

In the past few years alone, researchers have reported preliminary success with two sepa-

rate therapies that for the first time treat the underlying cellular disorder as opposed to Just the symptoms of the disease. More promising still, doctors are closing in on a technique for replacing the defective CF gene, which was discovered in 1989. The discovery has spaxxiied an unprecedented proposal to screen tens of millions of Americans for the defect, so that couples can avoid an affected child."This is a wonderful place to be right now”, says Michael Knowles, a CF researcher at the University of North Carolina. "Just a decade ago. these therapies were abstractions".

For half a century doctors have been treating cystic fibrosis symptom by symptom, doing their best to stein the rising tide of mucus triggered by the disease. As this abnormally thick fluid builds up in the. lungs, liver, pancreas and other organs, it not only -serves as a fertile ground for damaging infections but also blocks the passage of vital digestive enzymes to the intestine. As a result patients have difficulty breathing, digesting food and even reproducing. "This is a disease that simply wears you down", says Ramsey. Using simple therapies. such as clapping young patients on the back and chest several times a day to clear the lungs or providing a special nutrient, rich diet, scientists have made impressive strides against the ailment, extending the average life span from just five years in 1950s to 28 today. Recent advances in genetic engineering may have improved tactical approach further. One

drug. researchers have now learnt, promises to prevent a protein called elastase, produced In dangerous quantities by the CF patient's own immune cells, from attacking lung tissue. Another synthetic enzyme called DNase Instantly dissolves leftover DNA from dead immune cells, one of the bulkiest components of the ac-cunmlatlng mucus. The thinner fluid can then be cleared by the body's own mechanisms

Further advances have been made to stop the build-up of fluid at its source. In the early 1980s. scientists at the university of North Carolina opened the way for a radically new kind of therapy that would attempt Just that. The doctors noticed that cells taken from the lungs of CF patients contain abnormally high levels of

sodium and chloride-the constituents of salt. This did not. come as a complete surprise, since CF patient's sweat Is known to be abnormally salty, a sign that their bodies do not handle the mineral properly. But the U.N.C researchers realised that this imbalance in the lungs could explain why thick mucus was accumulating there. An excess of salt within cells was leaching water out of the mucus. This apparently was the basic defect behind the disease.

In the past few years, the U.N.C team concentrated on two drugs that could help repair cellular malfunction. One. a blood pressure medication, called amiloride, slows the uptake of sodium. The other containing naturally occurring substances called AFP and UTP (for Adenosine and Uridine Triphosphate), stimulates the secretion of chloride. Both have proved-*^fiecHut lr» early trials. • although a marketable treatment. researchers say. is still several years away.

Another therapy may be coming along sooner as Knowles predicts. Since Francis Collins and Lap-Chee Tsui discovered the CF gene on chromosome 7 in 1989, researchers from around the world have been struggling to devise a way to bring that finding to the bedside. The challenge: to transport corrected versions of the DNA into the lungs of CF patients. Dr. Ronald Crystal at the U.S. National Heart, lung and Blood Institute believes the best vehicles are cold viruses, which have a special fondness for the linings of the airways. Ordi-

narily, these viruses infect host cells by Injecting their own DNA through the target's outer membranes. Crystal hopes to harness this propensity by first disabling the microbes, so that they no longer cause colds, and then inserting a corrected version of the CF gene into the viral DNA.

When laboratory rats had this reconstructed virus sprayed into their tiny lungs, they not only absorbed the foreign gene but actually sprouted. In their airways, the human protein that scientists believe will cure CF. While crystal has yet to try the therapy In humans. he is supremely optimistic. “We now know it works in the test tube and in animals. I can guarantee that we can correct the defective protein in humans".

Another futuristic therapy Involves the manipulation of the errant protein Itself. The molecule which scientists have already reconstructed using the blueprint provided by the CF gene could conceivably be goaded into working with the right medication. Alternatively. doctors could Implant a healthy version of the CF gene in embryonic mice or goats, harvest the resulting protein from the adult animal's milk and then spray the protein into patient s lungs.

The discovery of CF gene has revolutionised the diagnosis of CF. Some public health experts in the U.S. believe that since doctors can identify the defective DNA (which occurs in 1 out of 25 Americans), they should screen all prospective parents. Men and women who find that they are both carriers might then choose to adopt or conceive with .doyon sperm 05 eggs. Only in the,recent past, the JJ.S, National Institute of Health financed a handful of pilot projects to help it decide whether massive screening programme would be worth the considerable cost.

For those already suffering from CF these are exciting. Younger patients have a fair chance of recovery. Brianna Oas' parents are a bit philosophical. “We're fully aware that whatever they come up with may not be in time for our daughter. People around the U.S. are now very hopeful. For the first time in the history of this devastating disease, that hope is warranted.

The author is controller of examinations, BUET