An estimated 60 million people, virtually all of them on the Indian subcontinent, carry a mutated gene that makes them all but certain to develop heart disease in their 40s and 50s and to suffer an early death, researchers are reporting today.
Though heart disease is the leading cause of death around the world, it is an even more serious problem in India. By next year, according to Indian scientists, the country will carry 60% of the world's burden of heart disease, and this defective gene may be the major reason why.
The gene is a mutant form of the gene that codes for a protein called cardiac myosin binding protein C, or MYBPC3, that is missing a 25-base-pair segment. It was discovered five years ago in two families with a high incidence of cardiomyopathy, in which the heart muscle becomes inflamed and doesn't work as well as it should.
Biochemist Perundurai S. Dhandapany of Madurai Kamaraj University in Madurai, India, and his colleagues initially studied 800 cardiac patients in nine cities in India and compared them to 699 carefully matched controls. They report today in the journal Nature Genetics that patients carrying one copy of the mutant gene are a staggering seven times more likely to develop heart disease than those without it, making them nearly certain to develop the disease.
Patients with the mutant gene appear healthy throughout the early part of their lives, but the abnormal protein manufactured from the gene slowly accumulates. After they turn 45 or so, the abundance of the abnormal protein triggers cardiomyopathy or other symptoms.
The team found only three people who had two copies of the abnormal gene. Two of them developed severe heart disease before the age of 3.
Next, the researchers screened 6,273 randomly selected individuals from 107 ethnic populations in India and found that in all of the groups -- including Hindus, Sikhs, Muslims and Christians -- a uniform 4% had the defect. The incidence was significantly higher in the western and southern states than in the northern states, however -- regions that have the highest incidence of heart disease in the country.
Finally, the researchers screened an additional 2,085 individuals from 70 ethnic groups in 26 other countries, including the United States. They found that the genetic defect is present only in India, Pakistan, Sri Lanka, Indonesia and Malaysia. They estimate that about 60 million people carry it.
Genetic analysis suggests that the mutation arose by chance in India about 33,000 years ago, after modern humans had immigrated to the Indian subcontinent from Africa. It then spread slowly to nearby countries, but remained largely restricted to the region.
It is unusual for such a deleterious genetic effect to persist in a population, noted co-author Chris Tyler-Smith of the Wellcome Trust Sanger Institute in Hinxton, U.K. But in this case, he noted, the gene does its dirty work after the carrier has passed through his or her reproductive years. "It's been able to spread because its effects usually develop only after people have had their children," he noted. It's "a case of chance genetic drift: simply terribly bad luck for the carriers."
Physicians should soon be able to screen for the mutation in parents and their offspring, Dhandapany said. When it is present, victims can be counseled to minimize their other cardiovascular risks to increase their chances of a longer life.
“You wait till Larry comes and I tell him my theory!” The bids, duly sealed, were given into the keeping of the commissary officer to be put in his safe, and kept until the day of judgment, when all being opened in public and in the presence of the aspirants, the lowest would[Pg 188] get the contract. It was a simple plan, and gave no more opportunity for underhand work than could be avoided. But there were opportunities for all that. It was barely possible—the thing had been done—for a commissary clerk or sergeant, desirous of adding to his pittance of pay, or of favoring a friend among the bidders, to tamper with the bids. By the same token there was no real reason why the commissary officer could not do it himself. Landor had never heard, or known, of such a case, but undoubtedly the way was there. It was a question of having the will and the possession of the safe keys. "Well, I believe our boys 's all right. They're green, and they're friskier than colts in a clover field, but they're all good stuff, and I believe we kin stand off any ordinary gang o' guerrillas. I'll chance it, anyhow. This's a mighty valuable train to risk, but it ought to go through, for we don't know how badly they may need it. You tell your engineer to go ahead carefully and give two long whistles if he sees anything dangerous." "Fine-looking lot of youngsters," he remarked. "They'll make good soldiers." "That's just what he was, the little runt, and we had the devil's own time finding him. What in Sam Hill did the Captain take him for, I'd like to know? Co. Q aint no nursery. Well, the bugler up at Brigade Headquarters blowed some sort of a call, and Skidmore wanted to know what it meant. They told him that it was an order for the youngest man in each company to come up there and get some milk for his coffee tomorrow morning, and butter for his bread. There was only enough issued for the youngest boys, and if he wanted his share he'd have to get a big hustle on him, for the feller whose nose he'd put out o' joint 'd try hard to get there ahead o' him, and get his share. So Skidmore went off at a dead run toward the sound of the bugle, with the boys looking after him and snickering. But he didn't come back at roll-call, nor at tattoo, and the smart Alecks begun to get scared, and abuse each other for setting up a job on a poor, innocent little boy. Osc Brewster and Ol Perry, who had been foremost in the trick had a fight as to which had been to blame. Taps come, and he didn't get back, and then we all became scared. I'd sent Jim Hunter over to Brigade Headquarters to look for him, but he came back, and said they hadn't seen anything of him there. Then I turned out the whole company to look for him. Of course, them too-awfully smart galoots of Co. A had to get very funny over our trouble. They asked why we didn't get the right kind of nurses for our company, that wouldn't let the members stray out of their sight? Why we didn't call the children in when the chickens went to roost, undress 'em, and tuck 'em in their little beds, and sing to 'em after they'd said 'Now I lay me down to sleep?' I stood it all until that big, hulking Pete Nasmith came down with a camp-kettle, which he was making ring like a bell, as he yelled out, 'Child lost! Child lost!' Behind him was Tub Rawlings singing, 'Empty's the cradle, baby's gone.' Then I pulled off my blouse and slung it into my tent, and told 'em there went my chevrons, and I was simply Scott Ralston, and able to lick any man in Co. A. One o' their Lieutenants came out and ordered them back to their quarters, and I deployed the company in a skirmish-line, and started 'em through the brush toward Brigade Headquarters. About three-quarters o' the way Osc Brewster and Ol Perry, when going through a thicket, heard a boy boo-hooing. They made their way to him, and there was little Skidmore sitting on a stump, completely confused and fagged out. He'd lost his way, and the more he tried to find it the worse he got turned around. They called out to him, and he blubbered out: 'Yes, it's me; little Pete Skidmore. Them doddurned fools in my company 've lost me, just as I've bin tellin' 'em right along they would, durn 'em.' Osc and Ol were so tickled at finding him that they gathered him up, and come whooping back to camp, carrying him every step of the way." And the rush stopped. Cadnan waited for a second, but there was no more. "Dara is not to die," he said. Then he saw Orion hanging over him, very low in the windy sky, shaking with frost. His eyes fixed themselves on the constellation, then gradually he became aware of the sides of a cart, of the smell of straw, of the movement of other bodies that sighed and stirred beside him. The physical experience was now complete, and soon the emotional had shaped itself. Memory came, rather sick. He remembered the fight, his terror, the flaming straw, the crowd that constricted and crushed him like a snake. His rage and hate rekindled, but this time without focus—he hated just everyone and everything. He hated the wheels which jolted him, his body because it was bruised, the other bodies round him, the stars that danced above him, those unknown footsteps that tramped beside him on the road. Farewell to Jane and Caroline!" HoME大香蕉色人阁
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