Prader-Willi syndrome is caused by a missing gene on chromosome 15. Normally, parents each pass down a copy of this chromosome. The defect can occur in a couple of ways: The father's genes are missing on chromosome 15.
: easy for the mind to understand or recognize. 1  It was obvious that things weren't working out. 2  Her reasons for leaving were obvious. = It's obvious why she left. 3  The answer seems obvious enough to me.  The problem was immediately obvious to everyone in the 1  room. He was the obvious candidate/choice for president.
The Macmillan Dictionary blog explores English as it is spoken around the world today. Free thesaurus definition of ways of saying that something is obvious or known from the Macmillan English Dictionary-a free English dictionary online with thesaurus and with pronunciation from Macmillan Publishers Limited.