After 12 years of searching, UCLA scientists have tracked down the first known gene mutation responsible for a heartbreaking disorder that kills newborn babies. Published in the April 1 online edition of the American Journal of Human Genetics, their findings will allow for earlier testing of embryos at risk for the disease. Scientists identify gene linked to deadly disorder in newborns
Many things go awry in short-rib polydactyly syndrome. The fetus develops extra fingers and toes and its skeleton doesn't grow, resulting in stunted ribs that prevent the lungs from maturing in the womb. Unable to breathe on its own, the child dies shortly after birth.
Parents currently must wait until the second trimester of pregnancy for a diagnosis - a long time to wait for potentially agonizing news about one's unborn child.
"Now that we've identified the genetic basis of the disease, families will be able to obtain a prenatal diagnosis within about 12 weeks," explained Dr. Deborah Krakow, associate professor of orthopedic surgery and human genetics at the David Geffen School of Medicine at UCLA. "Parents will also be able to screen embryos conceived in vitro to help select those free of the genetic mutation before uterine implantation."
Roughly one in 300 people are carriers of short-rib polydactyly syndrome. Both parents must carry the mutated gene in order for their child to inherit the disease.
In the hope of finding a common genetic link to the disease, the UCLA team studied DNA samples from three families whose children died of short-rib polydactyly syndrome. Dr. Stan Nelson, UCLA professor of human genetics, and his laboratory employed powerful genomic technology to rapidly test hundreds of thousands of gene variations in each fetus.
"It took scientists 10 years to map the human genome," Nelson said. "New technology enables us to search a child's entire genome in two weeks without testing the parents or other family members. It's a highly efficient way to quickly sample DNA and identify shared gene variations among people."
In the UCLA study, the research team identified a DNA sequence shared by all three infants from a single family. Like a signpost, it directed the scientists to a chromosomal location they suspected of housing the disease-causing gene.
"Each of us inherits different chromosomes from our mothers and fathers," explained Nelson. "If the child's genome contains the same DNA from both parents, we know that the mother and father are related in some way. They share a piece of ancestral DNA -- a common red flag for people known to have or carry a genetic disease."
After narrowing her search to three identical regions on the genome, Krakow zeroed in on one as the likely culprit. Her hunch proved correct. Not only did she identify the mutation in the initial family that lost three children, but she confirmed its presence in two other families whose infants also died of the disease.
Krakow and Nelson's next step will be to seek out other genes that contribute to short-rib polydactyly syndrome and uncover how these factors interact to cause the disorder.
"One of the reasons this disease is hard to crack is that it is caused by multiple genes, not just one," said Krakow. "We are searching for other gene variants in other families affected by the syndrome."
The DNA-scanning techniques developed by Nelson and his colleagues can be used to identify any hereditary disease-causing gene. The findings will enhance doctors' abilities to determine individual genes' specific roles and provide a more complete picture for healthy and abnormal human development.
Roughly 3 percent of all infants are born with birth defects. Some 5 percent of these children suffer from genetic defects affecting the skeleton. In this group, about 5 percent are short-rib polydactyly syndrome patients.
“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 ENTER NUMBET 0017
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Liberal Eugenics
Superhappiness?
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The End of Suffering
Wirehead Hedonism
The Good Drug Guide
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
MDMA: Utopian Pharmacology
Transhumanism: Brave New World?
Critique of Aldous Huxley's Brave New World
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