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Henry Angelman

pediatrician

syndrome

incapacitated

key sequence of DNA

Chromosome 15

paradox

Prader-Willi syndrome

Named after Henry Angelman, the pediatrician who first described Angelman syndrome. He referred to them as happy puppet children because it described, to some extent, the features. They have a rather jerky sort of movement when they are walking. These children have no speech. They are severely incapacitated in terms of learning, but are uncharacteristically happy as they are smiling all the time.
The condition was caused by a genetic fault: a key sequence of DNA was missing, deleted from Chromosome 15.
Then we came across a paradox: at the same time, er, the same change, the same little deletion of Chromosome 15 had been clearly associated with a quite different syndrome, much milder in terms of, er, of intellectual impairment, the Prader-Willi syndrome. These children are characterized by being very floppy at birth, but once they started eating properly and so on, they then had an insatiable appetite and would get very, very large.
What Pembrey saw simply made no sense. Here were two completely different diseases, Angelman syndrome and Prader-Willi syndrome being caused by exactly the same genetic fault.

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